DC-DC converter with a constant on-time pulse width modulation controller
First Claim
1. A DC-DC converter for converting an input voltage into an output voltage, comprising:
- an input node, receiving the input voltage;
an output node, providing the output voltage to a load;
an inductor coupled between the output node and a first node;
a first transistor coupled between the input node and the first node;
a second transistor coupled between the first node and a ground;
a control unit coupled to the first transistor and the second transistor, driving the first transistor and the second transistor; and
a Pulse Width Modulation (PWM) controller, comprising;
an error amplifier, receiving a reference voltage and the output voltage to generate an error signal according to a difference between the reference voltage and the output voltage;
a first comparator, comparing the error signal with a ramp signal to generate a trigger signal;
a PWM generator coupled between the first comparator and the control unit, generating a PWM signal with a fixed turn-on time, wherein a frequency of the PWM signal is adjusted according to the trigger signal, the input voltage and the output voltage; and
a ramp generator, generating the ramp signal according to the PWM signal, the input voltage and the output voltage,wherein the PWM controller provides the PWM signal to control the first transistor and the second transistor, so as to convert the input voltage into the output voltage,wherein the PWM generator comprises;
a current generating unit, providing a first current corresponding to the input voltage when the trigger signal is triggered and providing a second current in response to the first current;
a capacitor coupled between the current generating unit and the ground, wherein the capacitor is charged by the second current when the trigger signal is triggered; and
a second comparator, comparing a voltage of the capacitor with a voltage corresponding to the output voltage to generate the PWM signal.
1 Assignment
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Accused Products
Abstract
A DC-DC converter including a Pulse Width Modulation (PWM) controller for converting an input voltage into an output voltage is provided. The PWM controller includes an error amplifier, a comparator, a PWM generator and a ramp generator. The error amplifier generates an error signal according to a difference between a reference voltage and the output voltage. The comparator compares the error signal with a ramp signal to generate a trigger signal. The PWM generator generates a PWM signal with a fixed turn-on time, wherein a frequency of the PWM signal is adjusted according to the trigger signal, the input and output voltages. The ramp generator generates the ramp signal according to the PWM signal, the input voltage and the output voltage.
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Citations
22 Claims
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1. A DC-DC converter for converting an input voltage into an output voltage, comprising:
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an input node, receiving the input voltage; an output node, providing the output voltage to a load;
an inductor coupled between the output node and a first node;a first transistor coupled between the input node and the first node; a second transistor coupled between the first node and a ground; a control unit coupled to the first transistor and the second transistor, driving the first transistor and the second transistor; and a Pulse Width Modulation (PWM) controller, comprising; an error amplifier, receiving a reference voltage and the output voltage to generate an error signal according to a difference between the reference voltage and the output voltage; a first comparator, comparing the error signal with a ramp signal to generate a trigger signal; a PWM generator coupled between the first comparator and the control unit, generating a PWM signal with a fixed turn-on time, wherein a frequency of the PWM signal is adjusted according to the trigger signal, the input voltage and the output voltage; and a ramp generator, generating the ramp signal according to the PWM signal, the input voltage and the output voltage, wherein the PWM controller provides the PWM signal to control the first transistor and the second transistor, so as to convert the input voltage into the output voltage, wherein the PWM generator comprises; a current generating unit, providing a first current corresponding to the input voltage when the trigger signal is triggered and providing a second current in response to the first current; a capacitor coupled between the current generating unit and the ground, wherein the capacitor is charged by the second current when the trigger signal is triggered; and a second comparator, comparing a voltage of the capacitor with a voltage corresponding to the output voltage to generate the PWM signal. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A DC-DC converter for converting an input voltage into an output voltage, comprising:
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an input node, receiving the input voltage; an output node, providing the output voltage to a load; an inductor coupled between the output node and a first node; a first transistor coupled between the input node and the first node; a second transistor coupled between the first node and a ground; and a Pulse Width Modulation (PWM) controller, comprising; an error amplifier, receiving a reference voltage and the output voltage to generate an error signal according to a difference between the reference voltage and the output voltage; a sense unit, generating a sense current corresponding to a loading of the load; a compensation unit, generating a compensation signal according to the error signal and the sense current; a first comparator, comparing the compensation signal with a ramp signal to generate a trigger signal; a PWM generator, generating a PWM signal with a fixed turn-on time, wherein a frequency of the PWM signal is adjusted according to the trigger signal, the input voltage and the output voltage; and a ramp generator, generating the ramp signal according to the PWM signal, wherein the PWM controller provides the PWM signal to control the first transistor and the second transistor, so as to convert the input voltage into the output voltage. - View Dependent Claims (9, 10, 11, 12, 13, 14, 15)
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16. A DC-DC converter for converting an input voltage into an output voltage, comprising:
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an input node, receiving the input voltage; an output node, providing the output voltage to a load; an inductor coupled between the output node and a first node; a first transistor coupled between the input node and the first node; a second transistor coupled between the first node and a ground; and a Pulse Width Modulation (PWM) controller, comprising; an error amplifier, receiving a reference voltage and the output voltage to generate an error signal according to a difference between the reference voltage and the output voltage; a sense unit, generating a sense current corresponding to a loading of the load; a compensation unit, generating a compensation signal according to the sense current and a ramp signal, and comprising a first resistor and a first capacitor connected in series for compensating the error signal; a first comparator, comparing the compensation signal with the error signal to generate a trigger signal; a PWM generator, generating a PWM signal with a fixed turn-on time, wherein a frequency of the PWM signal is adjusted according to the trigger signal, the input voltage and the output voltage; and a ramp generator, generating the ramp signal according to the PWM signal, the input voltage and the output voltage, wherein the PWM controller provides the PWM signal to control the first transistor and the second transistor, so as to convert the input voltage into the output voltage, wherein the PWM generator comprises; a current generating unit, providing a first current corresponding to the input voltage when the trigger signal is triggered and providing a second current in response to the first current; a second capacitor coupled between the current generating unit and the ground, wherein the second capacitor is charged by the second current when the trigger signal is triggered; and a second comparator, comparing a voltage of the second capacitor with a voltage corresponding to the output voltage to generate the PWM signal. - View Dependent Claims (17, 18, 19, 20, 21, 22)
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Specification