US 2005/0001657 A1Published application

Bi-polar PNP chopper

AssigneeInfineon Technologies AG

InventorBengt Berg

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Abstract

A switch comprises an input with two input lines and an input stage comprising four current controlled PNP-transistors and four resistors, and an output comprising two output lines, and arranged to receive a constant voltage on the input and on the output produce a variable voltage. The switch further comprises four constant current sources which are connected to the bases of the first, second, third and fourth transistor, respectively so that the transistors are saturated. The switch further comprises four alternating current sources which are connected to the emitters of the first, second, third and fourth transistor, respectively, so that the transistors alternately are conducting current from emitter to collector and from collector to emitter. Furthermore, an amplifier, a comparator and a method for tuning the working point of a power transistor can be provided using such a switch.

Claims13

Dependent claims

A switch comprising an input with a first and a second input line and an input stage comprising first, second, third and fourth current controlled PNP-transistors and first, second, third and fourth resistors, and an output comprising a first and a second output line, and wherein said switch is arranged to receive a constant voltage on said input and produce a variable voltage on said output, wherein

said first resistor is connected to said first input line and further to the emitter of said first transistor,
said second resistor is connected to said first input line and further to the emitter of said second transistor,
said third resistor is connected to said second input line and further to the emitter of said third transistor,
said fourth resistor is connected to said second input line and further to the emitter of said fourth transistor,
the collector of said first and fourth transistor is connected to said second output line,
the collector of said second and third transistor is connected to said first output line, and
first, second, third and fourth constant current sources are connected to the bases of said first, second, third and fourth transistor, respectively so that said transistors are conductive, and
first, second, third and fourth alternating current sources are connected to the emitters of said first, second, third and fourth transistor, respectively, so that the transistors alternately are conducting current from emitter to collector and from collector to emitter.

5 more elements

A chopper stabilised amplifier for amplifying a voltage comprising an input for receiving an input voltage to be amplified and an output for outputting said amplified voltage, said amplifier further comprises an input switch coupled to said input, a AC-amplifier, and an output switch coupled to said output and an oscillator coupled to said input switch and said output switch, wherein

said input switch is a first switch comprising an input with a first and a second input line and an input stage comprising first, second, third and fourth current controlled PNP-transistors and first, second, third and fourth resistors, and an output comprising a first and a second output line, and wherein said first switch is arranged to receive a constant voltage on said input and produce a variable voltage on said output, wherein
said first resistor is connected to said first input line and further to the emitter of said first transistor,
said second resistor is connected to said first input line and further to the emitter of said second transistor,
said third resistor is connected to said second input line and further to the emitter of said third transistor,
said fourth resistor is connected to said second input line and further to the emitter of said fourth transistor,
the collector of said first and fourth transistor is connected to said second output line,
the collector of said second and third transistor is connected to said first output line, and
first, second, third and fourth constant current sources are connected to the bases of said first, second, third and fourth transistor, respectively so that said transistors are conductive, and
first, second, third and fourth alternating current sources are connected to the emitters of said first, second, third and fourth transistor, respectively, so that the transistors alternately are conducting current from emitter to collector and from collector to emitter.

6 more elements

Dependencies are inferred from the claim text.