Dynamic temperature compensating circuit for power transistor converters

Claim 2

A dynamic temperature compensating circuit for biasing the bases of first and second transistors connected in common emitter configuration, having collector-emitter paths of the two transistors connected together in a current loop, comprising: a transformer having a primary coil connected to an input alternating current source, a first secondary coil having a first side connected to the base of a first one of said transistors, and a second secondary coil having a first side connected to the base of a second one of said transistors, with said primary and first and second secondary coils being poled in the same direction; a first and a second resistor having a common first node connected to a first D.C. potential, said first resistor being connected between said first node and either side of said first secondary coil and said second resistor being connected between said first node and either side of said second secondary coil; a first and second diodes connected in parallel and oppositely poled between the second side of said first secondary coil and a second node connected to the common emitters of said transistors; a third and fourth diodes connected in parallel and oppositely poled between the second side of said second secondary coil and said second node; a capacitor connected between said second side of said first secondary coil and a first side of said primary coil; a resistance connected between said second side of said second secondary coil and the second side of said primary coil; said second diode poled in the same direction as the base-to-emitter junction of said first transistor, forward biasing said first transistor by the diode forward bias potential, when said transformer saturates and said first transistor has been in its off-state, so as to promote instantaneous conduction by said first transistor thereby avoiding cross-over distortion; said diode forward bias potential of said second diode maintaining equality with the base-to-emitter forward bias potential of said first transistor over a range of temperatures; whereby the output characteristics of said current loop are compensated for temperature fluctuations.

Claim 3

The apparatus of claim 1, wherein: said third diode, poled oppositely to the base-emitter junction of said second transistor, reverse biasing said second transistor by the diode forward bias potential, when said transformer saturates and said first transistor has been in its off-state, preventing said second transistor from being on when said first transistor turns on.

Claim 4

The apparatus of claim 2, wherein: said fourth diode poled in the same direction as the base-emitter junction of said second transistor, forward biasing said second transistor by the diode forward bias potential, when said transformer saturates and said second transistor has been in its off-state, so as to promote instantaneous conduction by said second transistor thereby avoiding cross-over distortion; said diode forward bias potential of said fourth diode maintaining equality with the base-to-emitter forward bias potential of said second transistor over a range of temperatures.

Claim 5

The apparatus of claim 3, wherein: said first diode, poled oppositely to the base-emitter junction of said first transistor, reverse biasing said first transistor by the diode forward bias potential, when said transformer saturates and said second transistor has been in its off-state, preventing said first transistor from being on when said second transistor turns on.

Claim 6

The apparatus of claim 4, wherein: said second diode and said first transistor are composed of the same semi-conductor material; and said fourth diode and said second transistor are composed of the same semi-conductor material.

Claim 7

The apparatus of claim 5, which further comprises: an output transformer with a primary coil connected in said current loop and a feedback secondary coil coupled thereto, which serves as said input alternating current source.

Claim 8

The apparatus of claim 6, which further comprises: a secondary output coil coupled to said output transformer for outputting an alternating current; whereby said dynamic temperature compensating circuit operates in a D.C.-A.C. converter.

Claim 9

The apparatus of claim 7, which further comprises: a rectification means connected to the output of said secondary output coil, for outputting a direct current; whereby said dynamic temperature compensating circuit operates in a D.C.--D.C. converter.

Claim 10

A dynamic temperature compensating circuit for biasing the bases of first and second transistors connected in common emitter configuration, having collector-emitter paths of the two transistors connected together in a current loop, comprising: a transformer having a primary coil connected to an input alternating current source, a first secondary coil having a first side connected to the base of a first one of said transistors, and a second secondary coil having a first side connected to the base of a second one of said transistors, with said primary and first and second secondary coils being poled in the same direction; a first and a second resistor having a common first node connected to a first D.C. potential, said first resistor being connected between said first node and either side of said first secondary coil and said second resistor being connected between said first node and either side of said second secondary coil; a first and second diodes connected in parellel and oppositely poled between the second side of said first secondary coil and a second node connected to the common emitters of said transistors; a third and fourth diodes connected in parallel and oppositely poled between the second side of said second secondary coil and said second node; said transformer having a third secondary coil poled in the same direction as said primary coil; a capacitor connected between said second side of said first secondary coil and a first side of said third secondary coil; a resistance connected between said second side of said second secondary coil and a second side of said third secondary coil; said second diode poled in the same direction as the base-to-emitter junction of said first transistor, forward biasing said first transistor by the diode forward bias potential, when said transformer saturates and said first transistor has been in its off-state, so as to promote instantaneous conduction by said first transistor thereby avoiding cross-over distortion; said diode forward bias potential of said second diode maintaining equality with the base-to-emitter forward bias potential of said first transistor over a range of temperatures; whereby the output characteristics of said current loop are compensated for temperature fluctuations.

Claim 11

A dynamic temperature compensating circuit for biasing the bases of first and second transistors connected in common emitter configuration, having collector-emitter paths of the two transistors connected together in a current loop, comprising: a transformer having a primary coil connected to an input alternating current source, a first secondary coil having a first side connected to the base of a first one of said transistors, and a second secondary coil having a first side connected to the base of a second one of said transistors, with said primary and first and second secondary coils being poled in the same direction; a first and a second resistor having a common first node connected to a first D.C. potential, said first resistor being connected between said first node and either side of said first secondary coil and said second resistor being connected between said first node and either side of said second secondary coil; a first and second diodes connected in parellel and oppositely poled between the second side of said first secondary coil and a second node connected to the common emitters of said transistors; a third and fourth diodes connected in parallel and oppositely poled between the second side of said second secondary coil and said second node; said transformer having a third secondary coil poled in the same direction as said primary coil; a capacitor connected between said second side of said first secondary coil and a first side of said third secondary coil; a resistance connected between said second side of said second secondary coil and a second side of said third secondary coil; said second diode poled in the same direction as the base-to-emitter junction of said first transistor, forward biasing said first transistor by the diode forward bias potential, when said transformer saturates and said first transistor has been in its off-state, so as to promote instantaneous conduction by said first transistor thereby avoiding cross-over distortion; said diode forward bias potential of said second diode maintaining equality with the base-to-emitter forward bias potential of said first transistor over a range of temperatures; whereby the output characteristics of said current loop are compensated for temperature fluctuations.

Claim 12

A dynamic temperature compensating circuit for biasing the bases of first and second transistors connected in common emitter configuration, having collector-emitter paths of the two transistors connected together in a current loop, comprising: a transformer having a primary coil connected to an input alternating current source, a first secondary coil having a first side connected to the base of a first one of said transistors, and a second secondary coil having a first side connected to the base of a second one of said transistors, with said primary and first and second secondary coils being poled in the same direction; a first and second diodes connected in parallel and oppositely poled between the second side of said first secondary coil and a second node connected to the common emitters of said transistors; a third and fourth diodes connected in parallel and oppositely poled between the second side of said second secondary coil and said second node; said transformer having a third secondary coil poled in the same direction as said primary coil, a second side of said third secondary coil connected to said second side of said second secondary coil; a capacitor connected between said second side of said first secondary coil and a first side of said third secondary coil; a means for charging said capacitor in the proper direction so as to give a slight reverse bias to whichever of said first and second transistors is on and a slight forward bias to whichever of said first and second transistors is off during the time when said switching transients have died down; said second diode poled in the same direction as the base-to-emitter junction of said first transistor, forward biasing said first transistor by the diode forward bias potential, when said transformer saturates and said first transistor has been in its off-state, so as to promote instantaneous conduction by said first transistor thereby avoiding cross-over distortion; said diode forward bias potential of said second diode maintaining equality with the base-to-emitter forward bias potential of said first transistor over a range of temperatures; whereby the output characteristics of said current loop are compensated for temperature fluctuations.

Claim 13

A dynamic temperature compensating circuit for biasing the bases of first and second transistors connected in common emitter configuration, having collector-emitter paths of the two transistors connected together in a current loop, comprising: a transformer having a primary coil connected to an input alternating current source, a first secondary coil having a first side connected to the base of a first one of said transistors, and a second secondary coil having a first side connected to the base of a second one of said transistors, with said primary and first and second secondary coils being poled in the same direction; a first and second diodes connected in parallel and oppositely poled between the second side of said first secondary coil and a second node connected to the common emitters of said transistors; a third and fourth diodes connected in parallel and oppositely poled between the second side of said second secondary coil and said second node; said transformer having a third secondary coil poled in the same direction as said primary coil, a second side of said third secondary coil connected to said second side of said second secondary coil; a capacitor connected between said second side of said first secondary coil and a first side of said third secondary coil; a means for charging said capacitor in the proper direction so as to give a slight reverse bias to whichever of said first and second transistors is on and a slight forward bias to whichever of said first and second transistors is off during the time when said switching transients have died down; said second diode poled in the same direction as the base-to-emitter junction of said first transistor, forward biasing said first transistor by the diode forward bias potential, when said transformer saturates and said first transistor has been in its off-state, so as to promote instantaneous conduction by said first transistor thereby avoiding cross-over distortion; said diode forward bias potential of said second diode maintaining equality with the base-to-emitter forward bias potential of said first transistor over a range of temperatures; whereby the output characteristics of said current loop are compensated for temperature fluctuations.

Claim 14

The apparatus of claim 10, which further comprises a resistance connected in series between said second side of said second secondary coil and said second side of said third secondary coil.

Claim 15

The apparatus of claim 10 wherein said means for charging comprises a second resistance connected between said first side of said first secondary coil and either side of said second secondary coil.

Claim 16

The apparatus of claim 10 wherein said means for charging comprises a second resistance connected between said first side of said second secondary coil and either side of said first secondary coil.