A switching power source having a digital control system is provided. The switching power source includes a switching circuit 40 for switching an input power, an output circuit 50 for converting the switching output into a DC output, and a digital control 70. The digital control 70 is adapted to receive an output voltage analog signal AS1 and an output current analog signal AS2, and to convert the signals AS1 and AS2 into digital signals. It further functions to calculate, based on the digital s...

Various techniques directed to the digital control of a switching regulator are disclosed. In one aspect, a method for regulating an output level at a power converter output includes receiving a feedback signal representative of the output level at the power converter output. In response to a state of the power converter, at least one of the feedback signal or a threshold level is adjusted. A feedback state signal is generated having a first feedback state that represents that the output level i...

In a power supply apparatus which is used for an image forming apparatus, even when a resonance frequency extremely changes due to an influence by an inductance load just after a fluorescent lamp was lit on and after completion of the stabilization after the light-on, the apparatus can immediately follow such a change and can generate a stable voltage. The apparatus is constructed by a comparator for comparing an output value of a secondary winding of a transformer and a predetermined value, fir...

A power-supply and communication circuit is based on a flyback converter with a transformer (6) whose primary winding (10) is periodically connected to a supply voltage by means of a switching element (8) in the rhythm of control pulses from an oscillator (24). Data communication to the secondary electronic circuitry (4) is effected by interrupting the control pulses in response to a first data signal (SDTA1) to be transmitted. The absence of the alternating voltage across the secondary winding ...

A DC/DC converter circuit to convert input source energy to output load energy, for example, a flyback converter to charge a defibrillation storage capacitor from a low-voltage battery in an implantable cardiac defibrillator. The converter allows input current to flow in the flyback inductor for a fixed time, and it allows output current to flow for a time directly proportional to average battery voltage and inversely proportional to the voltage on the capacitor being charged. When used near an ...

A high efficiency flyback converter with synchronous rectifying, uses an equivalent-conducting resistor of a synchronous switch coupled with the synchronous rectifier to detect the secondary current of a transformer. Included is a logic circuit to control the duty cycle of the synchronous switch to avoid the vibration of the driving pulse. There is no inductance element, such as a current sensor, in the main power circuit loop, so that the power efficiency will be increased. The driving pulse si...

An output isolated, switching power supply has a transformer with a primary and two secondaries, an electronic switch in series with the primary, a first rectifier and filter on the first secondary to provide bias power during both startup and operating modes, and a second rectifier and filter on the second secondary to provide regulated output power. A resistor-capacitor network on the primary side provide an initial operating condition, such as a single control pulse, to the electronic switch ...

The invention presents a switching control circuit for a primary-side-controlled power converter. A pattern generator produces a digital pattern to control a programmable capacitor that is connected to an oscillator, which produces frequency hopping to reduce the EMI. A voltage-waveform detector produces a voltage-feedback signal and a discharge-time signal by multi-sampling a voltage signal of a transformer. A current-waveform detector and an integrator generate a feedback signal. The integrati...

A close-loop PWM controller for a primary-side controlled power converter is provided. A voltage-waveform detector produces a voltage-feedback signal and a discharge-time signal. A current-waveform detector generates a current-waveform signal by measuring a primary-side switching current. An integrator generates a current-feedback signal by integrating the current-waveform signal with the discharge-time signal. A time constant of the integrator is correlated with a switching period of the switch...

The invention concerns a low voltage-to-high voltage converter of the flyback type. The converter includes a transformer whose primary winding is linked to a supply voltage source via a switch and whose secondary winding is linked to the terminals of a capacitor via a rectifier diode. This converter includes, in a conventional manner, a secondary regulation loop which compares the output voltage appearing at the terminals of the capacitor, via a divider bridge, with a reference voltage in order ...