Compensation circuit for transient response improvement
A circuit includes a compensation inductor, a compensation resistor, and a current emulation circuit. The current emulation circuit has a time constant smaller than a time constant of the compensation inductor and the compensation resistor. The current emulation circuit includes a sense resistor having a first terminal coupled with a first terminal of the compensation inductor, and a sense capacitor having a first terminal coupled with a second terminal of the sense resistor and a second terminal coupled with ground.
1 . A circuit comprising:
a resistor having a first terminal coupled to an inductor terminal, and a second terminal coupled to a capacitor terminal;
a current summing circuit having a first input coupled to a first current sense terminal, a second input coupled to a second current sense terminal, and an output; and
a controller including:
a compensator circuit having a first input, a second input, and an output, the first input coupled to the second terminal of the resistor, and the second input coupled to the output of the current summing circuit; and
a modulator circuit having an input coupled to the output of the compensator circuit.
2 . The circuit of claim 1 , further comprising:
a first capacitor coupled to the capacitor terminal; and
a second capacitor having a first terminal coupled to the second terminal of the resistor and to the first terminal of the first capacitor and a second terminal coupled to the first input of the compensator circuit.
3 . The circuit of claim 2 , wherein the resistor is a first resistor, and further comprising:
a second resistor having a terminal coupled to the first input of the compensator circuit; and
a third resistor having a first terminal coupled to the second terminal of the first resistor and to the first terminal of the first capacitor, and a second terminal coupled to the first terminal of the second capacitor.
4 . The circuit of claim 1 , further comprising an inductor coupled between the inductor terminal wherein the inductor has an associated resistance, in which a time constant of the inductor and the associated resistance is greater than a time constant of the first resistor and the first capacitor.
5 . The circuit of claim 4 , wherein the time constant of the first resistor and the first capacitor enables compensation for a combined sensed current signal at the output of the current summing circuit.
6 . The circuit of claim 5 , wherein the time constant of the first resistor and the first capacitor enables the compensation during transients of the combined sensed current signal.
7 . The circuit of claim 5 , wherein the compensation is responsive to a delay in the combined sensed current signal.
8 . The circuit of claim 5 , wherein the time constant of the first resistor and the first capacitor enables adjustment of an on time of a control signal at an output of the modulator circuit.
9 . A circuit comprising:
transformer circuitry including:
a first transformer including a first primary winding and a first secondary winding, the first secondary winding having first and second terminals; and
a second transformer including a second primary winding and a second secondary winding, the second secondary winding having a first terminal coupled to the second terminal of the first secondary winding and a second terminal coupled to a ground terminal;
an inductor having a first terminal coupled to the ground terminal and a second terminal coupled to the first terminal of the first secondary winding;
a first resistor having a first terminal coupled to the second terminal of the inductor, and a second terminal;
a capacitor having a first terminal coupled to the second terminal of the first resistor and a second terminal coupled to the ground terminal;
a second resistor having a terminal; and
a third resistor having a first terminal coupled to the second terminal of the first resistor and to the first terminal of the capacitor, and a second terminal coupled to the terminal of the second resistor.
10 . The circuit of claim 9 , wherein the capacitor is a first capacitor, and further comprising a second capacitor having a first terminal coupled to the second terminal of the third resistor and a second terminal coupled to the terminal of the second resistor.
11 . The circuit of claim 10 , wherein the inductor is a first inductor, and further comprising:
a second inductor coupled in parallel with the first primary winding, the second inductor having a terminal coupled to an output terminal, wherein a second terminal of the second resistor is coupled to the output terminal; and
a third inductor coupled in parallel with the second primary winding, the third inductor having a terminal coupled to the output terminal.
12 . The circuit of claim 10 , further comprising a controller having a feedback input coupled to the second terminal of the second capacitor and to the terminal of the second resistor, and having first and second current sense terminals, the controller including a current summing circuit having a first input coupled to the first current sense terminal and a second input coupled to the second current sense terminal.
13 . The circuit of claim 12 , wherein the inductor has an associated resistance, in which a time constant of the inductor and the associated resistance is greater than a time constant of the first resistor and the first capacitor.
14 . The circuit of claim 13 , wherein the time constant of the first resistor and the first capacitor is configured such that a signal at the feedback input includes compensation for a combined sensed current signal at an output of the current summing circuit.
15 . The circuit of claim 14 , wherein the time constant of the first resistor and the first capacitor is configured such that the compensation is provided during transients of the combined sensed current signal.
16 . The circuit of claim 14 , wherein the compensation is responsive to a delay in the combined sensed current signal.
17 . The circuit of claim 14 , wherein the time constant of the first resistor and the first capacitor enables adjustment of an on time of a pulse-width modulated control signal at an output of the controller.
18 . A system comprising:
a converter circuit including:
a first power stage having a first control input and a first output; and
a second power stage having a second control input and a second output;
an inductor having a first terminal coupled to a ground terminal, and a second terminal;
a resistor having a first terminal coupled to the second terminal of the inductor, and a second terminal;
a capacitor having a first terminal coupled to the second terminal of the resistor and a second terminal coupled to the ground terminal;
a controller having a feedback input coupled to the second terminal of the resistor and to the first terminal of the capacitor, a first current sense terminal coupled to the first output of the first power stage, and a second current sense terminal coupled to the second output of the second power stage, the controller including:
a current summing circuit having a first input coupled to the first current sense terminal and a second input coupled to the second current sense terminal;
a compensator having inputs coupled to an output of the current summing circuit and the feedback input; and
a modulator having an input coupled to an output of the compensator, and outputs coupled to the first and second control inputs of the first and second power stages.
19 . The system of claim 18 , wherein the capacitor is a first capacitor, and further comprising a second capacitor having a first terminal coupled to the second terminal of the resistor and to the first terminal of the first capacitor and a second terminal coupled to the feedback input of the controller.
20 . The system of claim 18 , wherein the resistor is a first resistor, and further comprising:
a second resistor having a terminal coupled to the feedback input of controller; and
a third resistor having a first terminal coupled to the second terminal of the first resistor and to the first terminal of the first capacitor, and a second terminal coupled to the first terminal of the second capacitor.
21 . The system of claim 20 , wherein the inductor has an associated resistance, in which a time constant of the inductor and the associated resistance is greater than a time constant of the first resistor and the first capacitor.
22 . The system of claim 21 , wherein the time constant of the first resistor and the first capacitor enables compensation for a combined sensed current signal at an output of the current summing circuit.
23 . The system of claim 22 , wherein the time constant of the first resistor and the first capacitor enables the compensation during transients of the combined sensed current signal.
24 . The system of claim 22 , wherein the compensation is responsive to a delay in the combined sensed current signal.
25 . The system of claim 22 , wherein the time constant of the first resistor and the first capacitor enables adjustment of an on time of a pulse-width modulated control signal at an output of the controller.
26 . The system of claim 18 , wherein the inductor is a first inductor, and further comprising:
transformer circuitry including:
a first transformer including a first primary winding having first and second terminals and a first secondary winding having first and second terminals, the first terminal of the first primary winding coupled to an output terminal that is coupled to a second terminal of the second resistor, the second terminal of the first primary winding coupled to a switching terminal of the first power stage, the first terminal of the first secondary winding coupled to the second terminal of the inductor; and
a second transformer including a second primary winding having first and second terminals and a second secondary winding having first and second terminals, the first terminal of the second primary winding coupled to the output terminal, the second terminal of the second primary winding coupled to a switching terminal of the second power stage, the first terminal of the second secondary winding coupled to the second terminal of the first secondary winding, and the second terminal of the second secondary winding coupled to a ground terminal;
a second inductor coupled in parallel with the first primary winding, the second inductor having a terminal coupled to the output terminal; and
a third inductor coupled in parallel with the second primary winding, the third inductor having a terminal coupled to the output terminal.