DC-DC converter circuit with synchronization module and corresponding conversion method

Patent metadata

Field	Value
Publication number	US-10720840-B2
Application number	US-201816222557-A
Country	US
Kind code	B2
Filing date	Dec 17, 2018
Priority date	Dec 22, 2017
Publication date	Jul 21, 2020
Grant date	Jul 21, 2020

Abstract

A DC-DC converter circuit including at least: a first step down converter having a first pair of switching devices in a half bridge configuration. A second step down converter includes a second pair of switching devices in a half bridge configuration. The first and second step down converters are connected in parallel to an output node connected to an output coil and receive command signals. A feedback loop includes a synchronization module receiving the gate control signals of high side switching devices and adjusts as a function of the gate control signals a delay in a signal path from the command signal to each gate control signal of the high side switching device to synchronize the gate control signals.

First claim

The invention claimed is:

1. A DC-DC converter circuit, comprising: a first converter including a first switching device configured to receive a first control signal; a second converter including a second switching device configured to receive a second control signal, wherein said first and second converters are connected in parallel to a switching node configured to be connected to an output coil, and wherein said first and second converters receive a logical command signal; and a synchronization module configured to receive the first and second control signals of the first and second switching devices, said synchronization module configured to adjust as a function of said first and second control signals respective first and second delays in respective first and second signal paths from the logical command signal to each the first and second control signals to synchronize the first and second control signals, wherein said synchronization module further comprises: a detector circuit configured to sense rising edges of the first and second control signals and configured to generate a pair of sense signals in response to the sensed rising edges of the first and second control signals, each sense signal indicating the rising edge of a corresponding one of the first and second control signals; a difference integration circuit configured to calculate a difference between said sense signals and to integrate said difference to generate a delay control signal; and an adjustable differential delay circuit coupled to receive said delay control signal and configured to modify, under control of the delay control signal, the respective delay in the respective signal path from the high side logical command signal to each of the first and second control signals of the high side switching devices to synchronize said rising edges of the first and second control signals.

2. The DC-DC converter circuit of claim 1 , wherein said detector circuit comprises two comparators, each comparator configured to compare a corresponding one of the first and second control signals with a reference voltage and configured to generate, based on the comparison, a corresponding one of the pair of sense signals.

3. The DC-DC converter circuit of claim 1 , wherein said difference integration circuit comprises a charge pump including a pair of current sources, each current source coupled through a respective switch to a node on which the delay control signal is provided and each of the current sources configured to be driven by a corresponding one of said sense signals to charge an output capacitor coupled to the node.

4. The DC-DC converter circuit of claim 1 , wherein said adjustable differential delay circuit comprises two voltage controlled delay circuits configured to receive the high side command signal and the delay control signal, each of the two voltage controlled delay controls circuits configured to apply a respective delay to the high side command signal to generate a corresponding delayed command signal.

5. The DC-DC converter circuit of claim 4 , wherein said adjustable differential delay circuit includes an inverting amplifier configured to negate the delay control signal before the delay control signal is supplied to one of the two voltage controlled delay circuits.

6. The DC-DC converter circuit of claim 4 , wherein said adjustable differential delay module in which one of the two voltage controlled delay circuits receives the delay control voltage and the other one of the two voltage controlled delay circuits receives a fixed voltage.

7. The DC-DC converter circuit of claim 1 , further comprising a negative current detection circuit configured to detect a negative current flowing in the output coil and configured to receive a voltage signal on said switching node and to generate a negative current detection signal that is provided to disable the detector circuit.

8. The DC-DC converter circuit of claim 7 , wherein said negative current detection circuit comprises a derivator module configured to sense a derivative of the voltage signal on the switching node.

9. The DC-DC converter circuit of claim 7 , wherein said negative current detection circuit comprises:
a derivator module including a core circuit including a single transistor and a matching reference transistor, the single transistor configured to generate a derivative signal based on the voltage signal on the switching node; and
a semilatch structure connected to the single transistor and the reference transistor and configured to operate as a sampler circuit, the semilatch structure configured to generate said negative current detection signal in response to the derivative signal.

10. The DC-DC converter circuit of claim 1 , wherein each of the switching devices comprises a MOS transistor.

11. The DC-DC converter circuit according to claim 1 , wherein the first converter includes a first half bridge circuit including the first switching device, the second converter includes a second half bridge circuit including the second switching device, and the first and second half bridge circuits are connected to the output coil and are configured to drive the output coil.

12. A switching converter, comprising:
a first converter circuit including a first high side switching device coupled to a switching node and configured to receive a first command signal, the first converter circuit configured to generate a first control signal based on the first command signal and to provide the first control signal to control switching of the first switching device;
a second converter circuit including a second high side switching device coupled to the switching node and configured to receive a second command signal, the second converter circuit configured to generate a second control signal based on the first command signal and to provide the second control signal to control switching of the second switching device; and
a synchronization circuit coupled to the first and second converter circuits and configured to receive an input command signal, the synchronization circuit configured to generate the first and second command signals based on the input command signal, each of the first and second command signals having a respective delay relative to the input command signal and the synchronization circuit configured to adjust the respective delays of the first and second command signals based on the first and second control signals, wherein the synchronization circuit comprises a capacitance coupled to a control node and wherein the synchronization circuit is configured to control charging and discharging of the control node responsive to the first and second control signals to generate a delay control signal on the control node, the synchronization circuit further configured to adjust values of the respective delays of the first and second command signals based on the delay control signal.

13. The switching converter of claim 12 , wherein each of the converter circuits comprises a step down converter circuit.

14. The switching converter of claim 13 , wherein each of the step down converter circuits includes a half-bridge including the corresponding one of the first and second high side switching devices.

15. The switching converter of claim 12 , further comprising an additional step down converter circuit, wherein the synchronization circuit is further configured to adjust delays of respective command signals associated with each of the additional step down converter circuit based on respective control signals controlling the switching of a high side switching device in each of the at least one additional step down convert

Assignees

• St Microelectronics Des & Appl
• St Microelectronics Srl

Inventors

• Thomas Matthieu
• Suraci Michele
• Mazzucco Massimo

Classifications

• H02M1/0006

  Arrangements for supplying an adequate voltage to the control circuit of converters · CPC title

• H02M1/0009

  Devices or circuits for detecting current in a converter · CPC title

• H02M3/1584 Primary

  with a plurality of power processing stages connected in parallel · CPC title

• Y02B70/10

  Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes · CPC title

• H02M1/08

  Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters · CPC title