IC wherein a chopper-type buck regulator PNP switch supplies base current to the load

Claim 2

A chopper-type regulator circuit for stabilizing an output voltage, comprising: a single-structure output transistor composed of a PNP-type transistor for switching an input current to a first output terminal; and a control section for controlling the switching of said output transistor between ON and OFF states based upon a voltage difference between a reference voltage and the output voltage, such that said control section controls a duty ratio of the output voltage, wherein said control section includes a base current output terminal for supplying a base current of said output transistor to a load connected to said chopper-type regulator circuit, the base current being supplied to the load whenever said output transistor is in an ON state.

Claim 3

The chopper-type regulator circuit as defined in claim 1, wherein said output transistor includes a collector, said collector being connected directly to said first output terminal.

Claim 4

The chopper-type regulator circuit as defined in claim 1, further comprising: a metal frame mounted with said regulator circuit, said first output terminal and said base current output terminal extending from said metal frame; and a packing resin for sealing said regulator circuit.

Claim 5

The chopper-type regulator circuit as defined in claim 1, wherein said control section controls a pulse width of a voltage mode.

Claim 6

The chopper-type regulator circuit as defined in claim 4, wherein said control section includes: a voltage difference output means for outputting a voltage difference between the reference voltage and the output voltage; a comparison means for comparing the output signal from said voltage difference output means with a prescribed pulse signal so as to output a control signal; and a constant current means for drawing the base current so as to keep a value of the base current constant when said output transistor is in conducting state based upon the control signal, said constant current means being connected between a base of said output transistor and said base current output terminal.

Claim 7

The chopper-type regulator circuit as defined in claim 1, wherein said control section controls a pulse width of a current mode.

Claim 8

The chopper-type regulator circuit as defined in claim 6, wherein said control section includes: a voltage difference output means for outputting a voltage difference between the reference voltage and the output voltage; a comparison means for comparing an output from said voltage difference output means with a current flow in said output transistor so as to output a first set signal; a flip flop for switching said output transistor based upon the first set signal and a prescribed second set signal; and a constant current means for drawing the base current so as to keep a value of the base current constant when said output transistor is brought to a conducting state by said switching operation via said flip flop, said constant current means being connected between a base of said output transistor and said base current output terminal.

Claim 9

The chopper-type regulator circuit as defined in claim 1, wherein said control section includes a first transistor having a collector and an emitter, said emitter being connected to a base of said output transistor, and said collector being connected directly to said base current output terminal.

Claim 10

The chopper-type regulator circuit as defined in claim 8, wherein said control section further includes a second transistor having a base connected to a base of said first transistor, said second transistor having an emitter connected to the base of the output transistor.

Claim 11

The chopper-type regulator circuit as defined in claim 1, further comprising a circuit element connected between said first output terminal and said base current output terminal.

Claim 12

The chopper-type regulator circuit as defined in claim 10, wherein said circuit element is a coil.

Claim 13

The chopper-type regulator circuit as defined in claim 1, wherein said output transistor and said control section are integrated into a single semiconductor chip.

Claim 14

The chopper-type regulator circuit as defined in claim 12, further comprising a metal frame mounted with said semiconductor chip, said first output terminal and said base current output terminal extending from said metal frame.

Claim 15

The chopper-type regulator circuit as defined in claim 12, further comprising a packing resin for sealing said semiconductor chip.