DC-to-DC converter controllers including clamping or boosting subsystems, and associated methods
A DC-to-DC converter includes one or more switching circuits, a respective energy storage inductor electrically coupled to each of the one or more switching circuits, and a controller. The controller includes a current deficit signal generator, an integration subsystem, one or more modulators, and a clamping subsystem. The current deficit signal generator is adapted to generate a current deficit signal. The integration subsystem is adapted to integrate the current deficit signal to generate a modulator control voltage. The one or more modulators are adapted to control the one or more switching circuits to transfer power from an input power source to a load, based at least in part on the modulator control voltage. The clamping subsystem is adapted to shunt a portion of the current deficit signal away from the integration subsystem, to prevent the modulator control voltage from falling below a predetermined minimum permissible value.
1. A DC-to-DC converter, comprising:
one or more switching circuits;
a respective energy storage inductor electrically coupled to each of the one or more switching circuits; and
a controller, including:
a current deficit signal generator adapted to generate a current deficit signal, the current deficit signal representing a difference between a current command signal of the DC-to-DC converter and an actual current signal of the DC-to-DC converter,
an integration subsystem adapted to integrate the current deficit signal to generate a modulator control voltage,
one or more modulators adapted to control the one or more switching circuits to transfer power from an input power source to a load, based at least in part on the modulator control voltage, and
a clamping subsystem adapted to shunt a portion of the current deficit signal away from the integration subsystem, to prevent the modulator control voltage from falling below a predetermined minimum permissible value, the predetermined minimum permissible value being below a minimum threshold value of the modulator control voltage required for the one or more modulators to cause the one or more switching circuits to transfer power from the input power source to the load.
2. The DC-to-DC converter of claim 1 , the clamping subsystem comprising:
a voltage source adapted to generate a reference voltage having the predetermined minimum permissible value;
a first amplifier adapted to amplify a difference between the reference voltage and the modulator control voltage; and
a current control device controlled by an output of the first amplifier and adapted to shunt the portion of the current deficit signal away from the integration subsystem.
3. The DC-to-DC converter of claim 2 , the current control device comprising a transistor adapted to shunt the portion of the current deficit signal away from the integration subsystem.
4. The DC-to-DC converter of claim 3 , the current deficit signal generator comprising:
a first current source adapted to generate the current command signal, the current command signal being proportional to a difference between a desired output voltage of the DC-to-DC converter and an actual output voltage of the DC-to-DC converter; and
a second current source electrically coupled to the first current source, the second current source adapted to generate the actual current signal, the actual current signal being proportional to a sum of current flowing through each energy storage inductor.
5. The DC-to-DC converter of claim 4 , wherein:
the first current source is electrically coupled to the second current source at an integration node;
the integration subsystem is electrically coupled between the integration node and a modulator control node;
the integration subsystem is adapted to set a voltage at the modulator control node to the modulator control voltage; and
each of the one or more modulators is electrically coupled to the modulator control node.
6. The DC-to-DC converter of claim 5 , the integration subsystem comprising:
a second amplifier adapted to amplify a difference between a voltage at a common mode power supply rail and a voltage at the integration node, an output of the second amplifier being electrically coupled to the modulator control node; and
an impedance network electrically coupled between the integration node and the modulator control node.
7. The DC-to-DC converter of claim 1 , the DC-to-DC converter being a multi-phase buck-type converter.
8. A controller for a DC-to-DC converter, comprising:
a current deficit signal generator electrically coupled to an integration node, the current deficit signal generator adapted to generate a current deficit signal representing a difference between a current command signal of the DC-to-DC converter and an actual current signal of the DC-to-DC converter;
an amplifier including an inverting input, a non-inverting input, and an output, the inverting input electrically coupled to the integration node, the non-inverting input electrically coupled to a common mode power supply rail, and the output electrically coupled to a modulator control node;
one or more modulators adapted to control one or more switching circuits of the DC-to-DC converter to transfer power from an input power source to a load, based at least in part on a voltage at the modulator control node; and
a clamping subsystem adapted to shunt a portion of the current deficit signal away from the integration node, to prevent the voltage at the modulator control node from falling below a predetermined minimum permissible value, the predetermined minimum permissible value being below a minimum threshold value of the modulator control voltage required for the one or more modulators to cause the one or more switching circuits to transfer power from the input power source to the load.
9. The controller of claim 8 , the clamping subsystem comprising:
a voltage source adapted to generate a reference voltage having the predetermined minimum permissible value;
an additional amplifier adapted to amplify a difference between the reference voltage and the voltage at the modulator control node; and
a current control device controlled by an output of the additional amplifier and adapted to shunt the portion of the current deficit signal away from the integration node.
10. The controller of claim 9 , the current control device comprising a transistor adapted to shunt current away from the integration node.
11. The controller of claim 10 , the current deficit signal generator comprising:
a first current source adapted to generate the current command signal, the current command signal being proportional to a difference between a desired output voltage of the DC-to-DC converter and an actual output voltage of the DC-to-DC converter; and
a second current source electrically coupled to the first current source at the integration node, the second current source adapted to generate the actual current signal, the actual current signal being proportional to a sum of current flowing through the DC-to-DC converter.
12. The controller of claim 11 , further comprising an impedance network electrically coupled between the integration node and the modulator control node.
13. A method for controlling a DC-to-DC converter, comprising:
integrating a current deficit signal to generate a modulator control voltage;
generating control signals to control a switching circuit of the DC-to-DC converter based on at least the modulator control voltage to transfer power from an input power source to a load; and
preventing the modulator control voltage from falling below a predetermined minimum permissible value, the predetermined minimum permissible value being below a minimum threshold value of the modulator control voltage required to cause the switching circuit to transfer power from the input power source to the load.
14. The method of claim 13 , wherein:
the step of integrating comprises integrating the current deficit signal using an integration subsystem; and
the step of preventing comprises shunting a portion of the current deficit signal away from the integration subsystem.
15. The method of claim 14 , further comprising:
generating a current command signal proportional to a difference between a desired output voltage of the DC-to-DC converter and an actual output voltage of the DC-to-DC converter;
generating an actual current signal proportional to a sum of current flowing through each energy storage inductor of the DC-to-DC converter; and
obtaining the current deficit signal from a difference between the current command signal and the actual current signal.
16. A DC-to-DC converter, comprising:
one or more switching circuits;
a respective energy storage inductor electrically coupled to each of the one or more switching circuits; and
a controller, including:
a current deficit signal generator adapted to generate a current deficit signal, the current deficit signal representing a difference between a current command signal of the DC-to-DC converter and an actual current signal of the DC-to-DC converter,
an integration subsystem adapted to integrate the current deficit signal to generate a modulator control voltage at a modulator control node,
one or more modulators adapted to control the one or more switching circuits to transfer power from an input power source to a load, based at least in part on the modulator control voltage, and
a boosting subsystem adapted to inject current into the modulator control node to boost the modulator control voltage in response to a first signal indicating an operating mode change of the DC-to-DC converter.
17. The DC-to-DC converter of claim 16 , further comprising a capacitor communicatively coupling the first signal to the boosting subsystem.
18. The DC-to-DC converter of claim 16 , the first signal indicating the DC-to-DC converter is switching from a low power operating mode to a high power operating mode.