Circuit for suppression of leading edge spike switched current

Claim 2

A power switching circuit, comprising: a power switch; circuitry for determining an ON time of the power switch, including; sensing circuitry for determining a sensed current flow through the power switch, comparison circuitry for comparing the sensed current flow with a control signal, and suppression circuitry for canceling sensed current spikes in the sensed current flow at the initiation of the ON time by generating an opposing pulse signal of a polarity opposite the sensed current flow coexistent with the current spike and summing the sensed current spikes and the opposing pulse signal prior to application to the comparison circuitry.

Claim 3

A power switching circuit as defined in claim 1, wherein the suppression circuitry comprises: a ramp generator; a signal differentiating circuit connected for generating a differentiated ramp signal from an output of the ramp generator, and means for summing the differentiated ramp signal with the sensed current flow through the power switch.

Claim 4

A power switching circuit as defined in claim 2, wherein the signal differentiating circuit comprises a parallel connected resistor and capacitor connected in series with the output of the ramp generator.

Claim 5

A power switching circuit, comprising: an input for accepting an energy source; an output for accepting a load; a power switch for controlling energy flow from the input to the output; a control for the power switch, including; a sensing circuit for sensing current flow through the power switch as a proportional waveform, a reference signal input, a comparator for comparing the proportional waveform with the reference signal input, a suppression network for canceling spike signals in the proportional waveform at the initiation of turn-on of the power switch prior to its application to the comparator by generating an opposite polarity pulse signal and summing it with an output of the sensing circuit.

Claim 6

A power switching circuit, comprising: an input for accepting an energy source; an output for accepting a load; a power switch for controlling energy flow from the input to the output; a control for the power switch, including; a sensing circuit for sensing current flow through the power switch as a proportional waveform, a reference signal input, a comparator for comparing the proportional waveform with the reference signal input, a suppression network for canceling spike signals in the proportional waveform at the initiation of turn-on of the power switch prior to its application to the comparator by generating an opposite polarity pulse signal and summing it with an output of the sensing circuit.

Claim 7

A power switching circuit as defined in claim 4, wherein the suppression network includes a ramp generator synchronized with switching of the power switch and a circuit for differentiating a ramp output of the ramp generator whereby the output of the circuit for differentiating a ramp output is summed with an output of the sensing circuit.

Claim 8

A power switching circuit as defined in claim 5, wherein the circuit for differentiating includes a resistor and a capacitor connected in parallel.

Claim 9

A power switching circuit as defined in claim 6, wherein the sensing circuit includes a sensing resistor connected in series with the power switch.

Claim 10

A power switching circuit as defined in claim 7, and further including a voltage clamp at an input for accepting the proportional waveform of the comparator.

Claim 11

A switching mode converter, comprising: a switch; current mode regulation circuitry, including; means for initiating conduction through the switch, means for detecting a current waveform of a current in the switch, means for terminating conduction in the switch when the current waveform reaches a threshold value, and means for negating initial spike voltages in the current waveform by generating a pulse of opposite polarity and concurrent with the initial spike voltage.

Claim 12

A switching mode converter, comprising: a switch; current mode regulation circuitry, including; means for initiating conduction through the switch, means for detecting a current waveform of a current in the switch, means for terminating conduction in the switch when the current waveform reaches a threshold value, and means for negating initial spike voltages in the current waveform by generating a pulse of opposite polarity and concurrent with the initial spike voltage.

Claim 13

A switching mode converter as defined in claim 9 wherein the means for negating initial spike voltages includes a ramp generator synchronized with the means for initiating conduction through the switch; means for differentiating an output of the ramp generator; and means for summing an output of the means for differentiating with the current waveform.

Claim 14

A switching mode converter as defined in claim 10 wherein the means for differentiating includes a parallel resistive capacitive network.

Claim 15

A switching mode converter as defined in claim 11 wherein the means for detecting a current waveform of a current in the switch includes a current sensing means connected in series with the switch.

Claim 16

A switching mode converter as defined in claim 12 wherein the switch comprises a transistor switch.