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BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a DC-DC converter apparatus for converting a D.C.
input into a stabilized output of different voltages, and more
particularly, to reducing a standby current in the DC-DC converter
apparatus when the DC-DC converter apparatus is in a non-operative state.
2. Description of the Related Art
A DC-DC converter apparatus is typically used as a power source of a data
processing system for converting a D.C. input into a stabilized D.C.
output having an adequate voltage and adequate power capacity to be
supplied to a circuitry. A power source section is constructed by a
plurality of DC-DC converter apparatuses and each of the DC-DC converter
apparatuses supplies electric power to at least one load (i.e., the
circuitry). At least one of the DC-DC converter apparatuses may have a
main power supply circuit and a supplemental power supply circuit. The
main power supply circuit converts a D.C. input into a stabilized D.C.
output adequate for the load and supplies the converted D.C. output to the
load. The supplemental power supply circuit converts the D.C. input into a
plurality of D.C. outputs necessary for the operations of respective
sections of the DC-DC converter apparatus and supplies the plurality of
D.C. outputs of adequate voltages to the respective sections of the DC-DC
converter apparatus. The main power supply circuit and supplemental power
supply circuit are each constructed as a DC-DC converter. A D.C. power
input to the DC-DC converter apparatus is D.C. power converted from A.C.
power supplied from an A.C. power source by an AC-DC converter, for
example.
When electric power is supplied to a load, both the main power supply
circuit and the supplemental power supply circuit are operating. On the
other hand, when no electric power is supplied to the load, that is, when
the circuit of the load is not operating, the operation of the main power
supply circuit is interrupted but the supplemental power supply circuit is
still operating. The reason why the supplemental power supply circuit is
still operating even when the main power supply circuit is set in the
non-operative state is to set the main power supply circuit in the standby
state so that the main power supply circuit can be immediately operated
when necessary. Therefore, in the DC-DC converter apparatus, a current for
operating the supplemental power supply, that is, a standby current,
always flows.
When a large number of DC-DC converter apparatuses are used as the power
source section of the apparatus, however, the standby current becomes
large and an amount of heat generated in a power distribution unit for
supplying D.C. power to the DC-DC converter apparatuses becomes large.
Typically, the power distribution unit is constructed of AC-DC converters.
If the amount of generated heat becomes large, as described above,
however, it becomes necessary to increase the cooling capacity of the
power distribution unit. When the amount of generated heat of the power
distribution unit becomes larger and the heat of the power distribution
unit cannot be sufficiently radiated by natural air-cooling, a cooling fan
is used to forcedly cool the power distribution unit, thereby suppressing
the heat generation of the power distribution unit.
Thus, in the conventional DC-DC converter apparatus, even if the main power
supply circuit is interrupted, an unwanted power caused by a standby
current or the sum of the standby currents and the driving current for the
cooling fan is consumed. Further, when the cooling fan is driven, noise is
generated by the rotation of the fan.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a DC-DC
converter apparatus capable of effectively suppressing the power
consumption in a state in which the load is not operating.
It is a further object of the present invention to provide a DC-DC
converter apparatus which reduces unwanted power consumption.
A DC-DC converter apparatus of this invention includes a main converter
section, a supplemental power supply section, a main control section and a
supplemental control section. The main converter section is constructed as
a DC-DC converter for converting a D.C. input into a D.C. output having a
preset voltage. The main converter section also supplies the stabilized
D.C. power required for a load to the load. The supplemental power supply
section supplies D.C. power necessary for the operations of respective
sections of the DC-DC converter apparatus to the respective sections. The
supplemental control section controls the operation of the supplemental
power supply section to set the supplemental power supply section into the
operative state or non-operative state. The main control section controls
the operation of the main converter section based on an output obtained
when the supplemental power supply section is set in the operative or
non-operative state by the supplemental control section so as to set the
main converter into the operative state or non-operative state.
Typically, the main converter includes a main power supply circuit and the
supplemental power supply section includes a supplemental power supply
circuit including a DC-DC converter. The supplemental control section may
include an external signal processing section for controlling the
operative/non-operative state of the supplemental power supply section
according to an externally supplied signal. The supplemental control
section may include a switch circuit for controlling the
operative/non-operative state of the supplemental power supply section.
The main control section may include a sequence processing section for
controlling the operative/non-operative state of the main converter
section according to a preset sequence in relation to the operation of the
supplemental control section.
The above preset sequence causes the main converter section to be operated
after operating the supplemental power supply section at the time of
turn-ON of the power source of the DC-DC converter apparatus and causes
the operation of the supplemental power supply section to be interrupted
after interrupting the operation of the main converter section at the time
of turn-OFF of the power source of the DC-DC converter apparatus.
The main control section may include an output stabilizing section for
stabilizing the voltage of a power supply output of the main converter
section. Further, it is possible to provide an operation monitoring
section for monitoring whether the operation of the main converter section
is normal or abnormal.
In the DC-DC converter apparatus of this invention, when the supplemental
power supply section is set into the operative state by controlling the
operative/non-operative state of the supplemental power supply section by
the supplemental control section, the supplemental power supply section
converts a D.C. input into a preset D.C. voltage and supplies electric
power to respective sections of the DC-DC converter apparatus. When the
main control section specifies the operative or non-operative state of the
main converter section based on an output of the supplemental control
section obtained when the supplemental power supply section is set in the
operative or non-operative state, the main converter section converts the
D.C. input into a preset D.C. voltage and supplies electric power to the
load.
In order to interrupt the operation of the DC-DC converter apparatus and
set the same into the non-operative state, the main converter section is
not operated and the operation of the supplemental power supply section is
interrupted. Therefore, when the DC-DC converter apparatus is set in the
non-operative state, no standby current flows, thereby making it possible
to prevent generation of unwanted power consumption. Further, the
operation of the DC-DC converter apparatus can be started or interrupted
with the output thereof kept stable and without setting the output thereof
into an abnormal state, by operating the main converter section after the
supplemental power supply section is operated when the DC-DC converter
apparatus is operated, and by interrupting the operation of the
supplemental power supply section after the operation of the main
converter section is interrupted when the power source switch of the DC-DC
converter apparatus is turned OFF.
BRIEF DESCRIPTION OF THE DRAWINGS
Other objects and advantages of the invention will become apparent during
the following discussion in conjunction with the accompanying drawings, in
which:
FIG. 1 is a block diagram showing the whole construction of a power supply
including a DC-DC converter apparatus according to this invention;
FIG. 2 is a block diagram showing the construction of a DC-DC converter
apparatus according to a first embodiment of this invention;
FIG. 3 is a block diagram showing the construction of a DC-DC converter
apparatus according to a second embodiment of this invention;
FIG. 4 is a flowchart for illustrating the operation of the DC-DC converter
apparatus of FIG. 3;
FIG. 5 is a block diagram showing the construction of a DC-DC converter
apparatus according to a third embodiment of this invention;
FIG. 6 is a flowchart for illustrating the operation of the DC-DC converter
apparatus of FIG. 5;
FIG. 7 is a block diagram showing the construction of a DC-DC converter
apparatus according to a fourth embodiment of this invention;
FIG. 8 is a timing chart for illustrating the operation of the DC-DC
converter apparatus of FIG. 7;
FIG. 9 is a block diagram showing the construction of a DC-DC converter
apparatus according to a fifth embodiment of this invention;
FIG. 10 is a timing chart for illustrating the operation of the DC-DC
converter apparatus of FIG. 9;
FIG. 11 is a block diagram showing the construction of a DC-DC converter
apparatus according to a sixth embodiment of this invention;
FIG. 12 is a timing chart for illustrating the operation of the DC-DC
converter apparatus of FIG. 11;
FIG. 13 is a block diagram showing the construction of a DC-DC converter
apparatus according to a seventh embodiment of this invention;
FIG. 14 is a timing chart for illustrating the operation of the DC-DC
converter apparatus of FIG. 13.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Embodiments of this invention will now be described with reference to the
accompanying drawings.
The whole construction of a power supply including a DC-DC converter
apparatus according to a first embodiment of this invention is shown in
FIG. 1. The power supply shown in FIG. 1 includes a power distribution
unit 1, DC-DC converter apparatuses 2(1), . . . , 2(K), 2(K+1), . . . ,
2(N), a cooling fan 3, and the plurality of DC-DC converter apparatuses
2(1), . . . , 2(K), 2(K+1), . . . , 2(N) connected to a plurality of loads
4(A), 4(B), (C), . . . The power distribution unit 1 includes an AC-DC
converter, and converts an A.C. input into D.C. outputs and supplies the
outputs to the DC-DC converter apparatuses 2(1), . . . , 2(K), 2(K+1), . .
. , 2(N). The power distribution unit 1 also supplies electric power to
drive the cooling fan 3 for cooling all of the converter apparatuses.
The DC-DC converter apparatuses 2(1), . . . , 2(K), 2(K+1), . . . , 2(N)
convert D.C. inputs into stable D.C. outputs necessary for the respective
loads and supply the stable D.C. outputs to the respective loads 4(A),
4(B), 4(C), . . . For example, in the case of FIG. 1, the DC-DC converter
apparatuses 2(1) to 2(K) supply electric power to the load 4(A), and the
DC-DC converter apparatuses 2(K+1) and 2(N) supply electric power to the
corresponding loads 4(B) and 4(C).
The construction of each of the DC-DC converter apparatuses 2(1) to 2(N) of
FIG. 1 is shown in FIG. 2. In FIG. 2, a DC-DC converter apparatus 2.sub.1
represents any one of the DC-DC converter apparatuses 2(1) to 2(N) and the
DC-DC converter apparatus 2.sub.1 supplies electric power to a load 4
(which represents any one of the loads 4(A), 4(B), . . . ). The DC-DC
converter apparatus 2.sub.1 shown in FIG. 2 is a basic DC-DC converter
apparatus based on this invention, and the DC-DC converter apparatus
2.sub.1 includes a main converter section 11, supplemental power supply
section 12, main control section 13, supplemental control section 14,
external signal processing section 15 and sequence processing section 16.
The main converter section 11 converts a D.C. input into adequate D.C.
power which meets the condition required by the load 4 and supplies the
converted D.C. power to the load 4. The supplemental power supply section
12 converts a D.C. input into adequate D.C. outputs which meet the
conditions required by the respective sections of the DC-DC converter
apparatus 2.sub.1 and supplies the converted D.C. outputs to the
respective sections. The main converter section 11 includes a main power
supply circuit and the supplemental power supply section 12 includes a
supplemental power supply circuit.
The supplemental control section 13 controls the operation of the
supplemental power supply section 12 and selectively sets the supplemental
power supply section 12 into the operative or non-operative state.
The main control section 14 controls the main converter section 11
according to the operative/non-operative state of the supplemental power
supply section 12 controlled by the supplemental control section 13 to set
the main converter section 11 into the operative state or non-operative
state. In this case, the main control section 14 effects the control
operation for monitoring and stabilizing the output voltage of the main
converter section 11 in addition to the control operation for setting the
operative/non-operative state of the main converter section 11.
The external signal processing section 15 issues a control instruction to
the supplemental control section 13 in response to an external signal for
controlling the operative/non-operative state of the DC-DC converter
apparatus 2.sub.1.
The sequence processing section 16 operates the main converter section 11
after operating the supplemental power supply section 12 at the time of
turn-ON of the power source switch, that is, when the power supply by the
DC-DC converter apparatus 2.sub.1 is started, and the sequence processing
section 16 interrupts the operation of the supplemental power supply
section 12 after interrupting the operation of the main converter section
11 at the time of turn-OFF of the power source switch, that is, when the
power supply by the DC-DC converter apparatus 2.sub.1 is interrupted.
In the DC-DC converter apparatus 2.sub.1 shown in FIG. 2, for example, when
the supplemental control section 13 operates the supplemental power supply
section 12 according to an external signal via the external signal
processing section 15, the supplemental power supply section 12 converts a
D.C. input into adequate D.C. outputs required by the respective sections
of the DC-DC converter apparatus 2.sub.1. When the main control section 14
operates the main converter section 11 according to the operation of the
supplemental power supply section 12, the main converter section 11
converts a D.C. input into an adequate D.C. output and supplies the same
to the load 4.
When the operation of the DC-DC converter apparatus 2.sub.1 is interrupted,
the control operation for the main converter section 11 is not affected,
and at the same time, the operation of the supplemental power supply
section 12 is interrupted by the supplemental control section 13.
Therefore, no standby current flows and unwanted power consumption can be
effectively prevented.
Further, since the sequence processing section 16 controls the main control
section 14 to operate the main converter section 11 after operating the
supplemental power supply section 12 when the DC-DC converter apparatus
2.sub.1 starts supply of electric power and interrupts the operation of
the supplemental power supply section 12 after interrupting the operation
of the main converter section 11 when the DC-DC converter apparatus
2.sub.1 interrupts supply of electric power, an output of the main
converter section 11 can be interrupted in a stable state without causing
an abnormal voltage, for example.
The construction of the second embodiment of a DC-DC converter apparatus
according to this invention is shown in FIG. 3. Like the case of FIG. 2,
the DC-DC converter apparatus 2.sub.2 of FIG. 3 is used as any one of the
DC-DC converter apparatuses 2(1) to 2(N) of FIG. 1.
The DC-DC converter apparatus 22 of FIG. 3 includes a main power supply
circuit 21, supplemental power supply circuit 22, supplemental control
circuit 23, main control circuit 24, signal processing circuit 25, output
stabilizing circuit 26 and operation monitoring section 27.
The main power supply circuit 21 includes a DC-DC converter section 28
which is connected to the power distribution unit 1 of FIG. 1. The DC-DC
converter section 28 converts a D.C. output from the power distribution
unit 1 into a stabilized D.C. output required by the load 4 and supplies
the converted D.C. output to the load 4.
The supplemental power supply circuit 22 includes a DC-DC converter section
29 which is connected to the power distribution unit 1. The DC-DC
converter section 29 converts part of a D.C. output of the power
distribution unit 1 into D.C. outputs necessary for the operations of the
respective sections of the DC-DC converter apparatus 2.sub.2 and includes
a stabilizing circuit for stabilizing and supplying the output voltages to
the respective sections.
The signal processing circuit 25 receives an external signal for
controlling the turn-ON/turn-OFF of the power source of the DC-DC
converter apparatus 2.sub.2 and the like, that is, controlling the
operative/non-operative state of the DC-DC converter apparatus 2.sub.2
from a power supply control section (not shown) and operates the
supplemental control circuit 23 according to the received signal.
The supplemental control circuit 23 controls the operative/non-operative
state of the supplemental power supply circuit 22 in response to the
control signal from the signal processing circuit 25.
An operation output of the DC-DC converter section 29 of the supplemental
power supply circuit 22 is also supplied to the main control circuit 24
and operation monitoring circuit 27.
The main control circuit 24 is operated based on a signal from the
supplemental power supply circuit 22 to supply a control signal for
controlling the operative/non-operative state of the main power supply
circuit 21 to the output stabilizing circuit 26.
The output stabilizing circuit 26 controls the operative/non-operative
state of the main power supply circuit 21 in response to a signal from the
main control circuit 24, and at the same time, monitors and stabilizes an
output voltage of the main power supply circuit 21.
The operation monitoring circuit 27 checks whether the operation of the
main power supply circuit 21 is abnormal or not according to an output of
the main power supply circuit 21. Further, the operation monitoring
circuit 27 is operated by supply of the power from the supplemental power
supply circuit 22. For example, the operation monitoring section 27
monitors the overcurrent, overvoltage, low voltage, abnormal temperature
and the like in the DC-DC converter apparatus 2.sub.2, and when an
abnormal condition is detected, an adequate measure such as generation of
an alarm sound, an alarm display, an interruption of operation or an
abnormal condition recovering process is taken according to the content of
the abnormal condition.
The operation of the DC-DC converter apparatus 2.sub.2 of FIG. 3 is
explained with reference to the flowchart shown in FIG. 4.
When the process is started, whether the process is completed or not is
first determined (step 90). If the process is not completed, the signal
processing circuit 25 waits for reception of a power supply turn-ON signal
for starting the operation of the DC-DC converter apparatus 22 from the
power supply control section (not shown) or a power supply turn-OFF signal
for interrupting the operation of the DC-DC converter apparatus 2.sub.2
(step 101). When receiving the power supply turn-ON signal or power supply
turn-OFF signal, the signal processing circuit 25 determines whether the
signal is the power supply turn-ON signal or power supply turn-OFF signal
(step 102).
If the received signal is determined to be the power supply turn-ON signal
in the step 102, the supplemental control circuit 23 starts the operation
of the supplemental power supply circuit 22 in response to the power
supply turn-ON signal (step 103). Then the DC-DC converter section 29 of
the supplemental power supply circuit 22 converts electric power which is
part of a D.C. output from the power distribution unit 1 into D.C. outputs
necessary for the respective sections of the DC-DC converter apparatus
2.sub.2, supplies the same and stabilizes the output voltage (step 104).
The main control circuit 24 issues an instruction for operation of the
main power supply circuit 21 to the output stabilizing circuit 26 in
response to an output of the supplemental power supply circuit 22 (step
105).
The output stabilizing circuit 26 starts the operation of the main power
supply circuit 21 in response to the operating instruction (step 106).
When the main power supply circuit 21 is operated, the DC-DC converter
circuit 28 converts a D.C. input from the power distribution unit I into a
stabilized D.C. output for the load 4 and supplies the D.C. output to the
load 4 (step 107).
Further, the output stabilizing circuit 26 controls the DC-DC converter 28
to stabilize the output voltage of the main power supply circuit 21 while
monitoring the output voltage of the main power supply circuit 21 (step
108). Then, the step 90 is effected again, and when the process is
completed, the process is terminated (step 100).
If the process is not completed and a next process to be effected remains,
the step 100 is effected again.
On the other hand, if the received signal is determined to be the power
supply turn-OFF signal in the step 102, the supplemental control circuit
23 interrupts the operation of the supplemental power supply circuit 22 in
response to the power supply turn-OFF signal (step 113). Interruption of
the operation of the supplemental power supply circuit 22 causes an output
of the DC-DC converter section 29 to be interrupted (step 114). Further,
the main control circuit 24 issues an instruction for canceling the
operating instruction to the output stabilizing circuit 26 in response to
the operation interruption (step 115).
The output stabilizing circuit 26 interrupts the operation of the main
power supply circuit 21 in response to cancellation of the operating
instruction (step 116). When the operation of the main power supply
circuit 21 is interrupted, the step 90 is effected again, and if the
process is completed, the process is terminated (step 100). If the process
is not completed and a next process to be effected remains, the step 101
is effected.
Specifically, the determination in the step 90 whether the process is
completed or not is made such that the process is determined to be
completed when a main switch of the device having the power source
contained therein is turned OFF to completely turn OFF the power source
and the process is not determined to be completed in the other case, for
example.
Thus, in the DC-DC converter apparatus 2.sub.2, since the main power supply
circuit 21 is not operated and the operation of the supplemental power
supply circuit 22 is interrupted when the operation of the DC-DC converter
apparatus is interrupted, no standby current flows. Therefore, since
unwanted power consumption can be prevented and it becomes unnecessary to
operate the cooling fan 3 because of the reduction in the power
consumption at the time of interruption of the operation of the DC-DC
converter apparatus, the power consumption can be further reduced.
Further, since the operation monitoring section 27 monitors the operation
of the main power supply circuit 21, an abnormal condition such as an
overcurrent can be detected, thereby enhancing the reliability of the
DC-DC converter apparatus.
The construction of a third embodiment of a DC-DC converter apparatus
according to this invention is shown in FIG. 5. Like the case of FIG. 2 or
FIG. 3, the DC-DC converter apparatus 2.sub.3 of FIG. 5 is used as any one
of the DC-DC converter apparatuses 2(1) to 2(N) of FIG. 1 and the same
reference numerals are attached to the same portions as those of FIG. 3.
The DC-DC converter apparatus 2.sub.3 of FIG. 5 is different from the DC-DC
converter apparatus 2.sub.2 of FIG. 3 in that a sequence processing
circuit 30 is provided between the supplemental power supply circuit 22
and the main control circuit 24.
The sequence processing circuit 30 supplies a control signal to the main
control circuit 24 according to a preset sequence based on an output of
the supplemental power supply circuit 22. In this case, the sequence
processing circuit 30 creates a control signal for controlling the main
control circuit 24 to operate the main power supply circuit 21 after
operating the supplemental power supply circuit 22 when the operation of
the DC-DC converter apparatus 2.sub.3 is started and interrupts the
supplemental power supply circuit 22 after operating the main power supply
circuit 21 when the operation of the DC-DC converter apparatus 2.sub.3 is
interrupted.
The operation of the DC-DC converter apparatus 2.sub.3 is explained with
reference to the flowchart of FIG. 6.
When the process is started, whether the process is completed or not is
first determined (step 90). When the process is not completed, the signal
processing circuit 25 waits for a power supply turn-ON signal for starting
the operation of the DC-DC converter apparatus 2.sub.3 from a power supply
control section (not shown) or a power supply turn-OFF signal for
interrupting the operation of the DC-DC converter apparatus 2.sub.3 (step
201). When receiving the power supply turn-ON signal or power supply
turn-OFF signal, the signal processing circuit 25 determines whether the
received signal is the power supply turn-ON signal or power supply
turn-OFF signal (step 202).
If it is determined in the step 202 that the received signal is the power
supply turn-ON signal, the supplemental control circuit 23 starts the
operation of the supplemental power supply circuit 22 in response to the
power supply turn-ON signal (step 203). Then, the DC-DC converter section
29 of the supplemental power supply circuit 22 converts electric power
which is part of a D.C. output of the power distribution unit 1 into D.C.
outputs necessary for the respective sections of the DC-DC converter
apparatus 2.sub.3, outputs the same and stabilizes the output voltages
(step 204).
The sequence processing circuit 30 outputs a control signal to the main
control circuit 24 after a preset period of time in response to the output
of the supplemental power supply circuit 22 so as to operate the main
power supply circuit 21 after the operation of the supplemental power
supply circuit 22 is started (step 205).
The main control circuit 24 issues an instruction for operation of the main
power supply circuit 21 to the output stabilizing circuit 26 in response
to an output of the sequence processing circuit 30 (step 206).
The output stabilizing circuit 26 starts the operation of the main power
supply circuit 21 according to the operating instruction (step 207). When
the main power supply circuit 21 is operated, the DC-DC converter section
28 converts a D.C. input from the power distribution unit 1 into a
stabilized D.C. output suitable for the load 4 and supplies the converted
D.C. output to the load 4 (step 208).
Further, the output stabilizing circuit 26 controls the DC-DC converter
section 28 while monitoring the output voltage of the main power supply
circuit 21 so as to stabilize the output voltage of the main power supply
circuit 21 (step 209). Then, the step 90 is effected again, and when the
process is completed, the process is terminated (step 100).
If the process is not completed and a next process to be effected remains,
the step 201 is effected.
On the other hand, if the received signal is determined to be the power
supply turn-OFF signal in the step 202, the supplemental control circuit
23 starts to interrupt the operation of the supplemental power supply
circuit 22 in response to the power supply turn-OFF signal (step 213) and
the voltage of the supplemental power supply circuit 22 is gradually
lowered (step 214). At this time, the sequence processing circuit 30
controls the main control circuit 24 to first interrupt the operation of
the main power supply circuit 21 and to then interrupt the operation of
the supplemental power supply circuit 22 (step 215).
By the above control operation, the main control circuit 24 issues an
instruction for cancellation of the operation instruction and rapid
interruption to the output stabilizing circuit 26 (step 216). The output
stabilizing circuit 26 interrupts the main power supply circuit 21
according to the instruction for rapid interruption (step 217). After the
operation of the main power supply circuit 21 is completely interrupted,
the operation of the supplemental power supply circuit 22 is completely
interrupted (step 218).
The above operation can be attained by adequately determining the time
constants of the main power supply circuit 21 and the supplemental power
supply circuit 22 set at the time of interruption. If a satisfactory
operation cannot be attained by determination of the time constants, it is
possible to control the operation of the supplemental power supply circuit
22 or supplemental control circuit 23 by use of the sequence processing
circuit 30. In this case, an output of the signal processing circuit 25 is
supplied to the sequence processing circuit 30 and the sequence processing
circuit 30 controls the main control circuit 24 and the supplemental power
supply circuit 22 or supplemental control circuit 23.
When the operations of the main power supply circuit 21 and the
supplemental power supply circuit 22 are interrupted, the step 90 is
effected again, and when the process is completed, the process is
terminated (step 100). If the process is not completed and a next process
to be effected remains, the step 201 is effected.
Thus, in the DC-DC converter apparatus 2.sub.3 of FIG. 5, in addition to
the effect obtained in the DC-DC converter apparatus 2.sub.2 of FIG. 3,
the effect that the stable starting and interruption can be attained
without causing an abnormal condition in the output voltage can be
obtained. This is because the sequence processing circuit 30 operates the
main power supply circuit 21 after operating the supplemental power supply
circuit 22 when the power source switch of the DC-DC converter apparatus
2.sub.3 is turned ON and interrupts the operation of the supplemental
power supply circuit 22 after interrupting the operation of the main power
supply circuit 21 when the power source switch of the DC-DC converter
apparatus is turned OFF.
The construction of a fourth embodiment of a DC-DC converter apparatus
according to this invention is shown in FIG. 7.
The DC-DC converter apparatus 2.sub.4 of FIG. 7 is a DC-DC converter
apparatus having a circuit construction obtained by more concretely
constructing the DC-DC converter apparatus 2.sub.3 of FIG. 5 and portions
which are substantially the same as those of FIG. 5 are denoted by the
same reference numerals.
A supplemental power supply circuit 22 of the DC-DC converter apparatus
2.sub.4 of FIG. 7 is not a so-called DC-DC converter in this example, and
is simply constructed as a stabilized power supply and includes a
transistor Q1, zener diode D1, capacitor C2 and resistor R10.
A supplemental control circuit 23 of the DC-DC converter apparatus 2.sub.4
includes resistors R11, R12 and transistor Q2.
A main control circuit 24 of the DC-DC converter apparatus 2.sub.4 includes
a comparator M, resistors R2, R3, R4 and capacitor C1.
A signal processing circuit 25 of the DC-DC converter apparatus 2.sub.4
includes a photo-isolator PI formed of a light emitting diode D3 and a
phototransistor Q5, diode D4 and resistors R1.
A sequence processing circuit 30 of the DC-DC converter apparatus 2.sub.4
includes transistors Q3, Q4, resistors R5, R13, R14, R15, R16, R17 and
zener diode D2.
The positive side (+) and negative side (-) of a D.C. input form the power
distribution unit 1 are respectively supplied to the positive side power
line and negative side power line of the DC-DC converter apparatus
2.sub.4.
The resistor R1 and diode D4 of the signal processing circuit 25 are
series-connected to two ends of the light emitting diode D3 of the
photo-isolator PI, respectively, and an external signal for controlling
turn-ON/turn-OFF (permission/interruption) of the power supply of the
DC-DC converter apparatus 2.sub.4 is supplied from a power control section
(not shown) to a series circuit of the resistor R1-light emitting diode
D3-diode D4. The emitter of the phototransistor Q5 is connected to the
negative side power line.
The resistor R11 of the supplemental control circuit 23 is connected
between the base and emitter of the transistor Q2 and the resistor R12 is
connected between the base of the transistor Q2 and the collector of the
phototransistor Q5.
The collector of the transistor Q1 of the supplemental power supply circuit
22 is connected to a positive side of the D.C. input, that is, an input
side of the positive side power line and the emitter thereof is connected
to an output side of the positive side power line. The resistor R10 is
connected between the collector of the transistor Q1 and the emitter of
the transistor Q2 of the supplemental control circuit 23. The zener diode
D1 is connected between the base of the transistor Q1 and the negative
side power line and the capacitor C1 is connected between the positive
side power line connected to the emitter of the transistor Q1 and the
negative side power line.
The zener diode D2 and resistor R13 of the sequence processing circuit 30
are serially connected. One end of the series circuit of the zener diode
D2 and resistor R13 which lies on the zener diode D2 side is connected to
the positive side power line connected to the emitter of the transistor
Q1. The other end of the above series circuit which lies on the resistor
R13 side is connected to the base of the transistor Q3. The emitter of the
transistor Q3 is connected to the negative side power line and the
resistor R14 is connected between the base and emitter of the transistor
Q3. The resistor R15 is connected between the collector of the transistor
Q3 and the emitter of the transistor Q1 and a series circuit of the
resistors R16 and R17 is connected between the collector and emitter of
the transistor Q3. The base of the transistor Q4 is connected to a
connection node between the resistors R16 and R17, the emitter of the
transistor Q4 is connected to the negative side power line, and the
collector of the transistor Q4 is connected to one end of the resistor R5.
The resistor R2 of the main control circuit 24 is connected between the
other end of the resistor R5 of the sequence processing circuit 30 and the
positive side power line connected to the emitter of the transistor Q1.
The capacitor C1 is connected between the resistor R2 and the negative
side power line. A series circuit of the resistors R3 and R4 is connected
between the positive side power line connected to the emitter of the
transistor Q1 and the negative side power line. One input terminal of the
comparator M is connected to a connection node between the resistor R2 and
the capacitor C1 and the other input terminal is connected to a connection
node between the resistors R3 and R4. An output of the comparator M is
supplied to the output stabilizing circuit 26.
The positive side (+) and negative side (-) of the D.C. input are connected
to the DC-DC converter section 28 of the main power supply circuit 21.
Positive and negative outputs of the DC-DC converter section 28 of the
main power supply circuit 21 are supplied to the load 4 as the positive
side (+) and negative side (-) of the D.C. output. The negative side power
line connected to the negative side (-) of the D.C. input is also
connected to the output stabilizing circuit 26 and operation monitoring
circuit 27. The positive side power line connected to the emitter of the
transistor Q1 is also connected to the output stabilizing circuit 26 and
operation monitoring circuit 27. An output of the DC-DC converter section
28 of the main power supply circuit 21, that is, the positive side (+) of
the D.C. output is input to the output stabilizing circuit 26 and an
output of the output stabilizing circuit 26 is supplied to the DC-DC
converter section 28 of the main power supply circuit 21.
FIG. 8 is a timing chart for illustrating the operation of the DC-C
converter apparatus 2.sub.4 of the fourth embodiment shown in FIG. 7.
The timing chart of FIG. 8 indicates the transition of a process from the
start of the operation of the DC-DC converter apparatus 2.sub.4 to the
interruption of the operation thereof with time, that is, a variation in
the position from the left to the right on the time base or abscissa.
The ordinates for the respective waves indicate voltages at points P.sub.A
to P.sub.G in FIG. 7. The voltages of the respective waveforms in FIG. 8
are normalized and the maximum levels thereof are indicated to be the
same, but in practice, the maximum voltages at the respective points
P.sub.A to P.sub.G are different.
Next, the operation of the DC-DC converter apparatus 2.sub.4 of the fourth
embodiment is specifically explained with reference to FIGS. 7 and 8.
First, at time t1, a D.C. input is supplied to the DC-DC converter
apparatus 2.sub.4 and an input voltage at the point P.sub.A is set into
the ON state ("+" level in FIG. 8). At this time, the power supply control
signal at the point P.sub.C in the signal processing circuit 25 is set in
the OFF state ("+" level in FIG. 8) and the phototransistor Q5 of the
photo-isolator PI is set in the OFF state. Therefore, the transistor Q2 of
the supplemental control circuit 23 is set in the OFF state and the
transistor Q1 of the supplemental power supply circuit 22 is set in the
OFF state so that the supplemental power supply circuit 22 will be kept
non-operative.
Next, at time t2, if the power supply control signal at the point P.sub.C
is set into the ON state ("-" level in FIG. 8), the light emitting diode
D3 of the photo-isolator PI emits light to turn ON the phototransistor Q5.
When the phototransistor Q5 is turned ON, a current flows into the
transistor Q5 via the resistors R10, R11 and R12 to lower the base voltage
of the transistor Q2 and the transistor Q2 is turned ON. Then, a collector
output of the transistor Q2 is supplied to the zener diode D1 to raise the
base voltage of the transistor Q1 and the transistor Q1 is turned ON.
When the transistor Q1 is turned ON, the emitter voltage of the transistor
Q1 at the point P.sub.B gradually rises as shown in FIG. 8 and the
supplemental power supply circuit 22 is operated to supply operating power
to the sequence processing circuit 30, main control circuit 24, output
stabilizing circuit 26 and operation monitoring circuit 27.
A rise in the emitter voltage of the transistor Q1 at the point P.sub.B
causes the collector voltage of the transistor Q3 at the point PD to rise.
When a rise in the collector voltage of the transistor Q3 causes breakdown
of the zener diode D2 at time t3, the transistor Q3 is turned ON to lower
the collector voltage of the transistor Q3 at the point P.sub.D and set
the same to the "-" level as shown in FIG. 8.
Since the transistor Q4 is turned OFF by a drop in the collector voltage of
the transistor Q3 at the point P.sub.D, one of the input voltages of the
comparator M at the point P.sub.E rises with the time constant determined
by the resistor R2 and the capacitor C1. Since the other input voltage of
the comparator M at the point P.sub.F is a voltage derived by dividing the
emitter voltage of the transistor Q1 by use of the resistors R3 and R4,
the waveform thereof becomes similar to the waveform of the emitter
voltage of the transistor Q1 as shown in FIG. 8. That is, the input
voltage of the comparator M at the point P.sub.E is used as an input
voltage which is compared in the comparator M and the other input voltage
of the comparator M at the point P.sub.F is used as a reference voltage
for comparison by the comparator M.
Then, when the input voltage of the comparator M at the point P.sub.E
becomes equal to or higher than the reference voltage at the point P.sub.F
at time t4, an output of the comparator M at the point P.sub.G is set into
the ON state to issue an instruction for operation of the main power
supply circuit 21 to the output stabilizing circuit 26. In response to the
operating instruction, the main power supply circuit 21 starts the
operation.
On the other hand, if the power supply control signal at the point P.sub.C
is set into the OFF state ("+" level in FIG. 8), the phototransistor Q5 of
the photo-isolator PI is turned OFF. When the phototransistor Q5 is turned
OFF, the transistor Q2 is turned OFF and the transistor Q1 is also turned
OFF so as to gradually lower the emitter voltage of the transistor Q1 at
the point P.sub.B and the supplemental power supply circuit 22 interrupts
generation of output after a preset period of time.
If the emitter voltage of the transistor Q1 at the point P.sub.B becomes
lower than a voltage (predetermined adequate voltage) determined by the
zener diode D2 at time t6 before the above emitter voltage becomes equal
to or lower than the reference voltage of the comparator M on the half-way
of lowering in the emitter voltage of the transistor Q1 at the point
P.sub.B, the transistor Q3 is turned OFF and the transistor Q4 is turned
ON.
At this time, the input voltage of the comparator M at the point P.sub.E is
lowered with the time constant determined by the resistor R5 and the
capacitor C1. When the input voltage at the point P.sub.E becomes equal to
or lower than the reference voltage of the comparator M at the point
P.sub.F, an output voltage of the comparator M is set into the OFF state
and the instruction for operation of the main power supply circuit 21 is
canceled to interrupt the operation of the main power supply circuit 21.
After the operation of the main power supply circuit 21 is interrupted, the
operation of the supplemental p | | |
