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US 7,627,053 B2Granted
Apparatus and method for driving a pulse width modulation reference signal
AssigneeTexas Instruments Incorporated
InventorsStefan W. Wiktor, Vladimir A. Muratov, Xuening Li
Life of this patent
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Abstract
An apparatus for driving a pulse width modulation reference signal includes: (a) A converting unit receiving an input signal at an input locus and presenting an output current at an output locus. The input signal varies at a first frequency. The output current is substantially related with the first frequency. (b) A capacitive element coupled with the output locus for charging by the output current. The pulse width modulation reference signal is related with voltage across the capacitive element.
Claims5
A frequency-to-current converter comprising:
- a one-shot unit including:
- a comparator having a first input terminal, a second input terminal, and an output terminal, wherein the first input terminal receives a reference voltage and the second input terminal receives a charging current;
- a first capacitor that is coupled to the second input terminal of the comparator;
- a flip-flop having a first input terminal and a second input terminal, wherein the first input terminal of the flip-flop is coupled to the output terminal of the comparator and the second input terminal of the flip-flop receives a clock signal;
- and
- a first switch that is coupled to the second input terminal of the comparator, wherein the first switch is actuated and deactuated by a signal output from the flip-flop;
- an averaging unit wherein, the averaging unit further comprises:
- a second switch that is actuated and deactuated by the signal output from the flip-flop;
- an amplifier having a first input terminal, a second input terminal, and an output terminal, wherein the first input terminal of the amplifier is coupled to the second switch;
- a resistor that is coupled between the output terminal of the amplifier and the first input terminal of the amplifier;
- and
- a second capacitor that is coupled between the output terminal of the amplifier and the first input terminal of the amplifier;
- and
- a voltage-to-current unit that is coupled to the averaging unit.
11 more elements
An apparatus comprising:
- a one-shot unit wherein, the one-shot unit further comprises:
- a comparator having a first input terminal, a second input terminal, and an output terminal, wherein the first input terminal receives a reference voltage and the second input terminal receives a charging current;
- a first capacitor that is coupled to the second input terminal of the comparator;
- a flip-flop having a first input terminal and a second input terminal, wherein the first input terminal of the flip-flop is coupled to the output terminal of the comparator and the second input terminal of the flip-flop receives a clock signal;
- and
- a first switch that is coupled to the second input terminal of the comparator, wherein the first switch is actuated and deactuated by a signal output from the flip-flop;
- an averaging unit wherein, the averaging unit further comprises:
- a second switch that is actuated and deactuated by the signal output from the flip-flop;
- an amplifier having a first input terminal, a second input terminal, and an output terminal, wherein the first input terminal of the amplifier is coupled to the second switch;
- a resistor that is coupled between the output terminal of the amplifier and the first input terminal of the amplifier;
- and
- a second capacitor that is coupled between the output terminal of the amplifier and the first input terminal of the amplifier;
- a voltage-to-current unit that is coupled to the averaging unit;
- a current mirror that is coupled to the voltage-to-current unit;
- a third capacitor that is coupled to the current mirror;
- and
- a third switch that is coupled generally in parallel to the third capacitor.
14 more elements
Dependencies are inferred from the claim text.