Transient suppression for boost regulator
First Claim
1. A circuit for generating an output voltage to a top node of a plurality of LED strings, comprising:
- an inductor having a load current flowing therethrough;
a switching transistor responsive to a switching control signal;
an integrator for generating a compensation voltage responsive to a voltage at a bottom node of an LED string and a reference voltage;
circuitry for combining an offset with the compensation voltage responsive to the compensation voltage and the load current through the inductor, wherein the offset is created only during a step load change of the load current and substantially reduces voltage transients from the compensation voltage and the output voltage;
a summation circuit for summing the compensation voltage including the offset with at least the voltage at the bottom node of the LED string to generate a first control signal;
a latch for generating the switching control signal responsive to the first control signal and a leading edge blanking signal.
3 Assignments
0 Petitions
Accused Products
Abstract
A circuit for generating an output voltage to a top node of a plurality of LED strings. The circuit includes an inductor having a load current flowing therethrough and a switching transistor responsive to a switching control signal. An integrator generates a compensation voltage responsive to a voltage at a bottom node of the LED string and a reference voltage. Circuitry for combining an offset with the compensation voltage is responsive to the compensation voltage and the load current through the inductor. The offset is generated only during a step load change of the load current and substantially reduces voltage transients from the compensation voltage and the output voltage. A summation circuit sums the compensation voltage including the offset with at least the voltage at the bottom node of the LED string to generate a first control signal. A latch generates the switching control signal responsive to the first control signal and a leading edge blanking signal.
15 Citations
17 Claims
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1. A circuit for generating an output voltage to a top node of a plurality of LED strings, comprising:
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an inductor having a load current flowing therethrough; a switching transistor responsive to a switching control signal; an integrator for generating a compensation voltage responsive to a voltage at a bottom node of an LED string and a reference voltage; circuitry for combining an offset with the compensation voltage responsive to the compensation voltage and the load current through the inductor, wherein the offset is created only during a step load change of the load current and substantially reduces voltage transients from the compensation voltage and the output voltage; a summation circuit for summing the compensation voltage including the offset with at least the voltage at the bottom node of the LED string to generate a first control signal; a latch for generating the switching control signal responsive to the first control signal and a leading edge blanking signal. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A circuit for generating an output voltage to a top node of a plurality of LED strings, comprising:
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an inductor having a load current flowing therethrough; a switching transistor responsive to a switching control signal; an integrator for generating a compensation voltage responsive to a voltage at a bottom node of the LED string and a reference voltage; circuitry for implementing a control algorithm for generating a digital value of an offset responsive to the compensation voltage and a step load change of the load current; a digital to analog converter for generating the offset in analog format responsive to the digital value of the offset; an adder circuit for adding the offset to the compensation voltage to substantial reduce the voltage transients from the compensation voltage and the output voltage; a summation circuit for summing the compensation voltage including the offset with at least the voltage at the bottom node of the LED string to generate a first control signal; and a latch for generating the switching control signal responsive to the first control signal and a leading edge blanking signal. - View Dependent Claims (8, 9, 10)
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11. A method for generating an output voltage to a top node of a plurality of LED strings, comprising the steps of:
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generating a compensation voltage responsive to a voltage at a bottom node of an LED string and a reference voltage; generating an offset voltage only during a step load change of the load current; combining the offset voltage with the compensation voltage, wherein the offset voltage substantially reduces voltage transients from the compensation voltage and the output voltage; summing the compensation voltage including the offset with at least the voltage at the bottom node of the LED string to generate a first control signal; generating a switching control signal responsive to the first control signal and a leading edge blanking signal; and generating the output voltage responsive to an input voltage and the switching control signal. - View Dependent Claims (12, 13, 14, 15, 16)
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17. A method for generating an output voltage to a top node of a plurality of LED strings, comprising the steps of:
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generating a compensation voltage responsive to a voltage at a bottom node of an LED string and a reference voltage; generating an offset voltage only during a step load change of the load current; combining the offset voltage with the compensation voltage, wherein the offset voltage substantially reduces voltage transients from the compensation voltage and the output voltage; summing the compensation voltage including the offset with at least the voltage at the bottom node of the LED string to generate a first control signal, wherein the step of summing further comprises the step of summing the compensation value, the voltage at the bottom node of the LED string, a slope compensation ramp signal and a current sense signal to generate the first control signal; generating a switching control signal responsive to the first control signal and a leading edge blanking signal; and generating the output voltage responsive to an input voltage and the switching control signal.
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Specification