Non-linear compensation ramp for current mode pulse width modulation
AssigneeIML International
InventorHenry H. Yuan
Life of this patent
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Abstract
A current mode direct current-to-direct current (DC-to-DC) voltage regulator controls its output voltage using a pulse width modulation (PWM) circuit that employs a non-linear compensation ramp. By employing such a PWM circuit, the output voltage can be controlled more robustly over a wider range of operating conditions.
Claims10
A voltage regulator comprising:
- an input terminal configured to be coupled to a voltage source;
- an output terminal configured to be coupled to a load;
- a pulse width modulation (PWM) circuit for generating an output having a desired voltage level at the output terminal, the PWM circuit including a switch that is pulsed ON and OFF based on a first voltage that is a function of a voltage ramp that increases non-linearly with respect to time and a second voltage that is a function of a voltage appearing at the output terminal;
- and
- an inductor disposed between the input terminal and the output terminal, wherein the switch controls current flow from the inductor to ground,
- wherein the first voltage is equal to a sum of a voltage level of the voltage ramp and a voltage level sensed from a point between the inductor and the switch, and the second voltage is a difference between a reference voltage and a voltage level proportional to the voltage level appearing at the output terminal.
A voltage regulator comprising:
- an inductor having a first port coupled to a voltage source and a second port coupled to an output terminal;
- and
- a switch connected to the first port of the inductor, the switch either permitting current flow from the inductor to ground or blocking current flow from the inductor to ground,
- wherein the switch is pulsed ON and OFF based in part on a voltage ramp that increases non-linearly with respect to time and a reference voltage, a voltage sensed at the second port of the inductor, and a voltage level proportional to a voltage level at the output terminal, and
- wherein the switch is turned OFF when a sum of the voltage level of the voltage ramp and the voltage sensed at the second port of the inductor is greater than a difference between the reference voltage and the voltage level proportional to the voltage level at the output terminal.
A method of controlling a voltage regulator including an inductor having a first port coupled to a voltage source and a second port to an output terminal, and a switch connected in series with the second port of the inductor between the inductor and ground, the method comprising:
- controlling the switch to permit current flow between the inductor and the ground at the beginning of periodic intervals;
- generating a signal having a voltage level that increases non-linearly with respect to time during each of the periodic intervals;
- and
- controlling the switch to block current flow between the inductor and the ground based in part on the voltage level of the generated signal,
- wherein the switch is controlled to block current flow between the inductor and the ground based on factors comprising a reference voltage, a voltage level at the output terminal, and a sensed voltage at the second port of the inductor, and
- wherein the switch is controlled to block current flow between the inductor and the ground when a sum of the sensed voltage and the voltage level of the generated signal is greater than a difference between the reference voltage and a voltage level proportional to the voltage level at the output terminal.
Dependencies are inferred from the claim text.