Texas Instruments Corporation

Benchmarq Microelectronics, Inc.

Mark Charles Fischer

Ken Richard King

A high frequency bipolar switching transistor circuit. A first bipolar transistor is provided, having an emitter adapted to receive a voltage, having a base adapted to receive a drive current, and having a collector. A second bipolar transistor is provided, having a base connected to the collector of the first bipolar transistor, having a collector connected to the base of the first bipolar transistor, and having an emitter. An inductor having a first port connected to the common connection node of the collector of the first bipolar transistor and the base of the second transistor, and having a second port connected to the emitter of the second transistor. The common connection node of the emitter of the second transistor and the second port of the inductor form the output of the circuit.

High frequency bipolar switching transistor

A control circuit is provided which includes a single programmable terminal for controlling a plurality of modes, functions or parameters in a programmable circuit with a minimum of program elements connected to the single programmable terminal. The program elements may illustratively be resistors, capacitors, inductors or other circuit components. In a first mode, for example, two program elements control a signal generating function in the programmable circuit. In a second mode, a voltage provided internally forces a condition at the programmable terminal to control another signal generating function. In both first and second modes, the values of the program elements, selectable by the user, also determine the particular frequencies of the respective generated signals. In a third mode, the signals generated in the first and second modes are compared to provide a control function. There is further provided an absolute value comparator responsive to either polarity of an input sense signal applied to a single sense terminal. A switched output results when the input exceeds a temperature compensated systematic offset inherent to the comparator without requiring any external threshold signal.

Control circuit having multiple functions set by a single programmable terminal

A switching regulator device for charging applications includes a transformer (18) which receives an AC input signal from an AC source (12) which is then rectified with a bridge rectifier (24). A regulation control circuit (26) is provided for regulating the output level of the bridge circuit (24) to a load (20). The regulation circuit (26) includes a switching element (62) which is operable to draw current from the AC source (12) in a periodic manner. The on/off duty cycle of the control to the switching element (62) will allow energy to be stored in a leakage inductance (36) of the transformer (18). The transformer (18) therefore comprises the switching inductance of a switching power supply with the leakage inductance (36) designed to provide adequate regulation for the voltage and current supplied to the load (10).

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Mark Charles Fischer