A regulation circuit for providing timing gate signals to the dc power section of a power supply, the regulation circuit utilizing phase angle conduction of a programmable unijunction transistor. The conduction angle is determined by the occurrence of the cycles of the ac source voltage unless earlier conduction is determined by the sensed dc voltage. Early conduction occurs when the control voltage to the PUT is allowed to build up beyond a predetermined level when the sensed dc voltage is low. When the sensed dc voltage is high, an electronic switch closes to discharge a storage element to prevent control voltage build up and, hence, early conduction. Ac source voltage failure also causes closing of the electronic switch to prevent undue regulation of the power section output at such times and to permit storage capacitors therein to maintain a dc output until source voltage is reestablished. Soft start elements in the form of long time constant components ensure against the application of peaked voltages during initial start up and in the presence of power surges.
The invention relates to a device particularly adapted for use with the power supply of a computer for controlling the regulating facilities in an electric high-power AC-DC converter of the power supply. This control device (D) comprises a regulation (CC) control comparator connected to the storage facilities (S) of the converter and receiving a reference voltage having a "nominal" value when the converter is normally powered by an AC network and receiving a portion of the output voltage from the converter, the output of said control comparator (CC) supplying an error signal to the regulating facilities (MR) of the converter. The control device also includes facilities (R) for supplying a variable reference voltage to the control comparator (CC) so that at the moment of recovery of the network following a cutoff, the voltage at the input of the filtering facilities (F) of the converter is, at the most, equal to the output voltage of the storage facilities (S).
An overcurrent protection circuit wherein excessive current flow to current handling components triggers a programmable unijunction transistor which activates a crow-bar device to clamp off current flow through the current handling components. The overcurrent protection circuit finds utility in protecting solid state circuits from overcurrent situations, and is characterized by rapid response time on an order of less than one microsecond.
A programmable control circuit is disclosed for generating a programmable power curve and ramp. The circuit includes an amplifier having both positive and negative feedback. The positive feedback including a time lag component and the negative feedback including a gain component. The circuit output is easily programmable by varying the component values and/or the input signal. In one embodiment, the rate of change of the control circuit's output waveform may be modified. In another embodiment, the circuit controls the start-up power supplied to a load. In yet another embodiment, the circuit is a waveform generator.
