Current mode controlled DC-to-DC converter
An apparatus having an input voltage and an output voltage is provided. The apparatus comprises a switch that receives the input voltage and that is adapted to be coupled to a load, a modulator having a timing signal, a compensator that is coupled to the modulator and that includes an amplifier, an overcurrent circuit, and a sampler. The modulator is coupled to the switch and the modulator actuates the switch at a first frequency. The amplifier amplifies the difference between at least a portion of the output voltage with a predetermined reference voltage and outputs an amplified voltage. The overcurrent circuit receives the amplified voltage and outputs an overcurrent signal to the modulator. The sampler is interposed between the amplifier and the overcurrent circuit and is coupled to the modulator, where the sampler samples the amplified voltage prior to each actuation of the switch based on the timing signal and where the sampler outputs the compared voltage that was sampled to the overcurrent circuit through the duration of each actuation of the switch.
1. An apparatus having an input voltage and an output voltage, the apparatus comprising:
a switch that receives the input voltage and that is adapted to be coupled to a load;
a modulator having a timing signal, wherein the modulator is coupled to the switch and wherein the modulator actuates the switch at a first frequency; and
a compensator that is coupled to the modulator, wherein the compensator includes:
an amplifier that amplifies the difference between at least a portion of the output voltage with a predetermined reference voltage and that outputs an amplified voltage;
an overcurrent circuit that receives the amplified voltage and outputs an overcurrent signal to the modulator, wherein overcurrent circuit includes:
a voltage-to-current converter;
a first FET that is gated by the voltage-to-current converter;
a second FET coupled in series with the first FET, wherein the second FET is gated by an actuation signal from the modulator; and
a comparator that receives the voltage from a node between the first and second FETs; and
a sampler interposed between the amplifier and the overcurrent circuit and coupled to the modulator, wherein the sampler samples the amplified voltage prior to each actuation of the switch based on the timing signal, and wherein the sampler outputs the compared voltage that was sampled to the overcurrent circuit through the duration of each actuation of the switch.
2. The apparatus of claim 1 , wherein the modulator further comprises:
an oscillator that generates the timing signal; and
a latch that receives the timing signal and outputs the actuation signal at the first frequency.
3. The apparatus of claim 2 , wherein the latch is an RS latch.
4. The apparatus of claim 1 , wherein the compensator further comprises a voltage divider that receives the output voltage.
5. The apparatus of claim 1 , wherein the sampler is a sample-and-hold amplifier.
6. An apparatus having an input voltage and an output voltage, the apparatus comprising:
a bridge having a plurality of switches coupled in series to one another, wherein at least one of the switches receives the input voltage;
an inductor coupled to the node between two of the switches, wherein the inductor outputs the output voltage;
an oscillator that generates a clock signal;
a latch that receives the clock signal and that outputs a plurality of actuation signals to the bridge; and
a compensator that is coupled to the latch, wherein the compensator includes:
an amplifier that amplifies the difference between at least a portion of the output voltage with a predetermined reference voltage and that outputs an amplified voltage;
an overcurrent circuit that receives the amplified voltage and outputs an overcurrent signal to the modulator, wherein overcurrent circuit includes:
a voltage-to-current converter;
a first FET that is gated by the voltage-to-current converter;
a second FET coupled in series with the first FET, wherein the second FET is gated by at least one of the plurality of actuation signals; and
a comparator that receives the voltage from a node between the first and second FETs; and
a sampler interposed between the amplifier and the overcurrent circuit and coupled to the oscillator, wherein the sampler samples the amplified voltage prior to each actuation of the switch based on the clock signal, and wherein the sampler outputs the compared voltage that was sampled to the overcurrent circuit through the duration of each actuation of the switch.
7. The apparatus of claim 6 , wherein the latch is an RS latch.
8. The apparatus of claim 6 , wherein the compensator further comprises a voltage divider that receives the output voltage.
9. The apparatus of claim 6 , wherein the sampler is a sample-and-hold amplifier.