Isolation and transforming circuit

Claim 2

In a power supplY system having a circuit for transmitting electrical energy from a source to a load, sensing circuit means associated with the transmitting circuit for sensing selected electrical characteristics of the transmitting circuit, control circuit means connected in responsive relation to said sensing circuit for controlling the selected characteristics of the energy and an isolation circuit for electrically isolating the control circuit from the sensing circuit, the isolating circuit comprising oscillator circuit means for generating a signal having a frequency which varies in response to variations in the electrical characteristic being sensed, pulse circuit means connected to said oscillator circuit means for producing variable duty cycle pulses in response to variations in frequency of said pulse producing circuit means, feedback circuit means connected to respond to sensed characteristics and connected to said pulseproducing circuit means and said oscillator circuit means to vary the frequency of the signal in response to variations in said sensed characteristic, and output circuit means electrically isolated from said duty cycle-producing means and responsive thereto to reproduce said duty cycle pulses in said output circuit, said output circuit being transformer coupled from said pulse circuit means, said pulse circuit means including a multivibrator circuit having a fixed ''''on'''' time and a variable total time, the duty cycle of said pulses from said pulse circuit means varying in accordance with the input signal from said sensing circuit means, said oscillator circuit including a voltage responsive semiconductor device and circuit means for producing a preset voltage signal, said input signal from said sensing circuit varying one of said voltage signals, said preset voltage being established by an active semiconductor device producing a voltage level when said oscillator circuit is oscillating and in a first state, said oscillator circuit including a programmable unijunction transistor having a gate electrode connected to said active semiconductor device.

Claim 3

In a power supplY system having a circuit for transmitting electrical energy from a source to a load, sensing circuit means associated with the transmitting circuit for sensing selected electrical characteristics of the transmitting circuit, control circuit means connected in responsive relation to said sensing circuit for controlling the selected characteristics of the energy and an isolation circuit for electrically isolating the control circuit from the sensing circuit, the isolating circuit comprising oscillator circuit means for generating a signal having a frequency which varies in response to variations in the electrical characteristic being sensed, pulse circuit means connected to said oscillator circuit means for producing variable duty cycle pulses in response to variations in frequency of said pulse producing circuit means, feedback circuit means connected to respond to sensed characteristics and connected to said pulse-producing circuit means and said oscillator circuit means to vary the frequency of the signal in response to variations in said sensed characteristic, and output circuit means electrically isolated from said duty cycle-producing means and responsive thereto to reproduce said duty cycle pulses in said output circuit, said output circuit being transformer coupled from said pulse circuit means, said pulse circuit means including a multivibrator circuit having a fixed ''''on'''' time and a variable total time, the duty cycle of said pulses from said pulse circuit means varying in accordance with the input signal from said sensing circuit means, said oscillator circuit including a voltage responsive semiconductor device and circuit means for producing a preset voltage signal, said input signal from said sensing circuit varying one of said voltage signals, said preset voltage being established by an active semiconductor device producing a voltage level when said oscillator circuit is oscillating and in a first state, said oscillator circuit including a programmable unijunction transistor having a gate electrode connected to said active semiconductor device.

Claim 4

In a power supplY system having a circuit for transmitting electrical energy from a source to a load, sensing circuit means associated with the transmitting circuit for sensing selected electrical characteristics of the transmitting circuit, control circuit means connected in responsive relation to said sensing circuit for controlling the selected characteristics of the energy and an isolation circuit for electrically isolating the control circuit from the sensing circuit, the isolating circuit comprising oscillator circuit means for generating a signal having a frequency which varies in response to variations in the electrical characteristic being sensed, pulse circuit means connected to said oscillator circuit means for producing variable duty cycle pulses in response to variations in frequency of said pulse producing circuit means, feedback circuit means connected to respond to sensed characteristics and connected to said pulse-producing circuit means and said oscillator circuit means to vary the frequency of the signal in response to variations in said sensed characteristic, and output circuit means electrically isolated from said duty cycle-producing means and responsive thereto to reproduce said duty cycle pulses in said output circuit, said output circuit being transformer coupled from said pulse circuit means, said pulse circuit means including a multivibrator circuit having a fixed ''''on'''' time and a variable total time, the duty cycle of said pulses from said pulse circuit means varying in accordance with the input signal from said sensing circuit means, said oscillator circuit including a voltage responsive semiconductor device and circuit means for producing a preset voltage signal, said input signal from said sensing circuit varying one of said voltage signals, said preset voltage being established by an active semiconductor device producing a voltage level when said oscillator circuit is oscillating and in a first state, said oscillator circuit including a programmable unijunction transistor having a gate electrode connected to said active semiconductor device.

Claim 5

The improvement of claim 1 wherein said active semiconductor device presents a relatively high impedance to the gate electrode of said unijunction transistor to cause triggering of said unijunction transistor.

Claim 6

The improvement of claim 2 wherein said oscillator circuit operates at a preselected frequency range greater than zero including a zero input signal from said sensing circuit means.

Claim 7

The improvement of claim 3 wherein said frequency of said oscillator circuit increases with increases in input signal from said sensing circuit means.

Claim 8

The improvement of claim 4 wherein the duty cycle of said pulse circuit means increases with increases in frequency, said feedback circuit means being connected to increase the frequency of said oscillator circuit means in response to increases in said input signal.

Claim 9

The improvement of claim 5 wherein said input to said oscillator circuit from said feedback circuit means comprises a variable voltage signal, said oscillator circuit means including a resistive capacitive timing circuit connected to said feedback circuit means.

Claim 10

The improvement of claim 6 wherein said unijunction transistor includes an input signal in response to the charge level on said capacitor, the signal in said feedback circuit varying the supply signal to charge said capacitor.

Claim 11

The improvement of claim 7 wherein said timing circuit, including said capacitor, is connected to the anode electrode of said unijunction transistor, said unijunction transistor being rendered conductive when the charge on said capacitor exceeds a preselected level.

Claim 12

The improvement of claim 8 wherein said active semiconductor device includes a transistor having a collector emitter circuit connected to the gate electrode of said unijunction transistor, the conduction of said unijunction transistor presenting relatively low impedance to said gate circuit to cause said unijunction transistor to cEase conduction.

Claim 13

The improvement of claim 9 wherein the output of said unijunction transistor is connected to the input circuit of said multivibrator circuit, said multivibrator circuit initiating the output pulse in response to the conduction of said unijunction transistor.

Claim 14

The improvement of claim 10 wherein said output pulse is of fixed duration and the generation of the next pulse from said oscillator circuit terminates the total time of a cycle from said multivibrator circuit, said total time and thus said duty cycle varying in response to the frequency of said oscillator.

Claim 15

The improvement of claim 11 wherein said feedback circuit includes a switch and an integrating circuit, said switch and said integrating circuit providing an average current in said feedback circuit to correspond to said frequency.

Claim 16

The improvement of claim 12 wherein said feedback circuit includes a current summing node, said current summing node including input currents from said sensing circuit and from said multivibrator circuit.

Claim 17

The improvement of claim 13 wherein the current in said feedback circuit to said charging circuit is a function of both said average current and said input signal current.

Claim 18

The improvement of claim 1 wherein said coupling transformer is differentially coupled to the output of said pulse circuit means for producing first and second output pulses from said transformer means, said first pulse corresponding to the start of the pulse from said multivibrator circuit, and said second pulse corresponding to the end of said multivibrator circuit.

Claim 19

The improvement of claim 15 wherein said output circuit includes a bistable circuit having a first and second state connected to said transformer, said first and second pulses switching said bistable means between said stable states.

Claim 20

The improvement of claim 16 wherein said bistable circuit means reproduces the pulse from said multivibrator means but electrically isolated therefrom.

Claim 21

The improvement of claim 14 wherein said coupling transformer is differentially coupled to the output of said pulse circuit means for producing a first and second output pulses from said transformer means, said first pulse corresponding to the start of the pulse from said multivibrator circuit, and said second pulse corresponding to the end of said multivibrator circuit.

Claim 22

The improvement of claim 18 wherein said output circuit includes a bistable circuit having a first and second state connected to said transformer, said first and second pulses switching said bistable means between said stable states.