Abstract: Programmable power supplies as used in automatic testing systems (ATS) require three commands from a computer; namely, polarity, gain and analog magnitude. Whether received from a general purpose bus such as the IEEE 488 or other means the commands are in parallel format and must be serialized. The three commands must be recognized and decoded and applied to the appropriate power supplies. The present invention in addition to furnishing the above responses, provides optical isolation to eliminate possible ground loops and other voltage difference problems. One significant simplification comprises the use of sample and hold amplifiers in place of the more conventional latches so that new commands can be accumulated without affecting the response to a prior command.

Abstract: A dynamic load for testing regulated power supplies comprises a pass transistor or transistors which are controlled by current or voltage regulating means operates under current regulation for loading a voltage regulated power supply and under voltage regulation for loading a current regulated power supply. Only a small bias voltage is required to keep the pass transistor in conduction when the terminal voltage of the power supply under test is programmed to zero output voltage. Otherwise the power required for the dynamic load power supply comes from the power supply under test. Programming the dynamic load power supply provides a complete range of loads to the power supply under test. Additionally, feedback from the power supply under test to the dynamic load power supply can cause the latter to simulate a fixed resistor load. The dynamic load power supply replaces a wide range of the conventional power resistors used for regulated power supply testing.

Abstract: Two high voltage power supplies having negative outputs with respect to common are combined to provide positive as well as negative output with respect to common. An operational preamplifier is used as an inverter. The combination includes provision for programming by means of a voltage returned to common making the system compatible with Conventional remote control systems.

Abstract: Two high voltage power supplies programmable by external voltage and each having their positive output terminals as common are combined so that the output has the negative terminal grounded. Also the input programming voltage is applied referenced to ground.

Abstract: A programmable amplifier includes an operational amplifier receiving an analog input signal of a given polarity and voltage range and a read only memory (ROM) control which actuates six switches in a resistor configuration connected to the amplifier in such a manner as to provide a selection of two gain factors and direct or inverted polarity output in response to combinations of digital signals on two input lines to the ROM.

Abstract: In a bipolar regulated power supply, two pass devices (transistors) are connected in a complementary symmetry circuit, one controlling the current from a positive voltage source and the other the current from a negative voltage source. One pass device connected in a first control loop is controlled by a source of input signals and feedback from the output terminal. A second control loop maintains a constant quiescent current in the two pass devices. In order to maintain this quiescent current in the presence of load current, a second feedback to the second loop, sensing load current, is provided.

Abstract: Increased versatility in crowbar overvoltage protection for regulated power supplies is provided by a tracking circuit which allows setting the overvoltage limit at a predetermined increment above a programmable output voltage. In addition provision is made for programming up the crowbar protection circuit rapidly to anticipate the rise of voltage in the main power supply and for delaying the programming down of the protection circuit to allow the main power supply voltage to decay without triggering the protection circuit.