Synchronous DC-DC regulator with shoot-through prevention
AssigneeKoninklijke Philips Electronics N.V.
InventorsPhilip Rutter, Leonardus De Groot, Nicolas J. Wheeler
Life of this patent
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Abstract
A synchronous dc—dc converter converts an input dc voltage to an output dc voltage. A control FET (6) and a sync FET (8) are connected in series between input dc voltage terminals (2,4). An alternating control signal input from a control circuit (18) controls the control and sync FETs (6,8) to be switched on alternately. At least one driver (30, 32) is provided to drive the FETs (6,8). In response to a change in the alternating control signal of a predetermined polarity, the driver (32) switches off the sync FET (8), and then the driver (30) waits for the trigger signal before switching on the control FET (6).
Claims10
A synchronous dc—dc converter circuit for converting an input dc voltage of predetermined polarity to an output dc voltage, the synchronous dc—dc converter circuit comprising:
- a dc input and a ground input for supplying the input dc voltage;
- a control FET having source and drain connected between the dc input and a switch node, the switch node being for connection through an inductor to a dc output for supplying the output dc voltage;
- a sync FET having source and drain connected between the switch node and the ground input;
- a switching input for inputting an alternating control signal;
- a comparator for detecting a voltage change on the switch node of opposite polarity to the dc input voltage and sending out a trigger signal in response;
- and
- at least one driver for driving the control and sync FETs alternately in response to the alternating control signal on the switching input,
- wherein the driver, in response to a change in the alternating control signal of a predetermined polarity, switches off the sync FET, and then waits for the trigger signal before switching on the control FET.
A high side component for a synchronous dc—dc converter circuit for converting an input dc voltage of predetermined polarity to an output dc voltage, the high side component comprising:
- a dc input for supplying the input dc voltage;
- a control FET having source and drain connected between the dc input and a switch node, the switch node being for connection through an inductor to a dc output for supplying the output dc voltage;
- a switching input for inputting an alternating control signal;
- a comparator for detecting a voltage change on the switch node of opposite polarity to the dc input voltage and sending out a trigger signal in response;
- and
- at least one driver for driving the control FET in response to the alternating signal on the switching input wherein in response to a change in polarity of the alternating signal of first predetermined sign the driver switches off the control FET and in response to a change in polarity of the alternating signal of second predetermined sign the driver waits for the trigger signal and then switches on the control FET.
A method of operating a synchronous dc—dc converter circuit having a control FET connected between an input dc terminal and a switch node and a sync FET connected between the switch node and a ground terminal, the method comprising:
- supplying an input dc voltage of predetermined polarity between the input dc terminal and the ground terminal;
- supplying a pause width modulated alternating signal to a switching input;
- and
- driving the control and sync FETs alternately in response to the alternating signal on the switching input, by:
- in response to a change in polarity of the alternating signal from a first polarity to a second polarity carrying out the steps of switching off control FET, detecting a voltage change on the switch node of opposite polarity to the dc input voltage, and then switching on the sync FET, and
- in response to a change of polarity of the alternating signal from the second polarity to the first polarity carrying out the steps of switching off the FET, detecting a voltage change on the switch node of opposite polarity to the dc input voltage, and then switching on the control FET said switching node being connected through an inductor to a dc output for supplying the dc output voltage.
Dependencies are inferred from the claim text.