Current feed-through adaptive voltage position control for a voltage regulator
In a voltage regulator including an error amplifier to generate a first signal related to an output voltage of the voltage regulator, a current sense circuit to generate a second signal related to an inductor current of the voltage regulator, and a PWM comparator to generate a PWM signal in response to the first and second signals to regulate the output voltage, a current feed-through adaptive voltage position control comprises supplying ramp signal and offset signal to modify the PWM signal to thereby eliminate the offset of the output voltage.
1. A voltage regulator comprising:
an error amplifier for generating a first signal related to an output voltage of the voltage regulator;
a current sense circuit for generating a second signal related to an inductor current of the voltage regulator;
a PWM comparator for generating a PWM signal in response to the first and second signals to regulate the output voltage;
a ramp injection circuit for supplying a ramp signal, the ramp signal being proportional to a product of the output voltage and an on-time of the PWM signal;
an offset injection circuit for supplying an offset signal; and
a summing circuit having inputs coupled to the current sense circuit, the ramp injection circuit and the offset injection circuit, and an output coupled to the PWM comparator, the offset signal being subtracted from the ramp signal and applied to the second signal to modify the PWM signal, whereby an offset of the output voltage is substantially eliminated.
2. The voltage regulator of claim 1 , wherein the ramp signal and offset signal are inputted to the PWM comparator.
3. The voltage regulator of claim 1 , wherein the ramp signal and offset signal are input to the error amplifier.
4. The voltage regulator of claim 1 wherein the ramp signal is input to the PWM comparator, and the offset signal is input to the error amplifier.
5. The voltage regulator of claim 1 , wherein the offset signal is input to the PWM comparator, and the ramp signal is input to the error amplifier.
6. A current feed-through adaptive voltage position control method for a voltage regulator, comprising the steps of:
generating a PWM signal in response to a first signal related to an output voltage of the voltage regulator and a second signal related to an inductor current of the voltage regulator for regulating the output voltage;
wherein the PWM signal is modified by a ramp signal, the ramp signal being proportional to a product of the output voltage and an on-time of the PWM signal, and an offset signal applied to the second signal, whereby an offset of the output voltage is substantially eliminated.
7. The control method of claim 6 , wherein the PWM signal is directly modified by the ramp signal and offset signal.
8. The control method of claim 6 , wherein the error signal is modified by the ramp signal and offset signal to further modify the PWM signal.
9. The control method of claim 6 , wherein the ramp signal directly modifies the PWM signal, and the error signal is modified by the offset signal to further modify the PWM signal.
10. The control method of claim 6 , wherein the offset signal directly modifies the PWM signal, and the error signal is modified by the ramp signal to further modify the PWM signal.