Boost devices with active diodes and switch-mode converters thereof

Patent metadata

Field	Value
Publication number	US-10033260-B2
Application number	US-201514957163-A
Country	US
Kind code	B2
Filing date	Dec 2, 2015
Priority date	Aug 20, 2015
Publication date	Jul 24, 2018
Grant date	Jul 24, 2018

Abstract

A switch-mode converter includes a high-side driver, a high-side transistor, a low-side driver, a low-side transistor, a capacitor, and an active diode. The high-side driver is supplied by the bootstrap voltage of the bootstrap node and a floating reference voltage of a floating reference node, and generates the high-side output signal. The high-side transistor provides an input voltage to the floating reference node according to the high-side output signal. The low-side driver generates the low-side output signal. The low-side transistor couples the floating reference node to a ground according to the low-side output signal. The capacitor is coupled between the bootstrap node and the floating reference node. The active diode provides the supply voltage to the bootstrap node. When the bootstrap voltage exceeds the supply voltage, the active diode isolates the supply voltage from the bootstrap node.

First claim

What is claimed is:

1. A switch-mode converter, comprising:
a high-side driver, supplied by a bootstrap voltage of a bootstrap node and a floating reference voltage of a floating reference node, and generating a high-side output signal;
a high-side transistor, providing an input voltage to the floating reference node according to the high-side output signal;
a low-side driver, generating a low-side output signal;
a low-side transistor, coupling the floating reference node to a ground according to the low-side output signal;
a capacitor, coupled between the bootstrap node and the floating reference node; and
an active diode, providing a supply voltage to the bootstrap node, wherein, when the bootstrap voltage exceeds the supply voltage, the active diode isolates the supply voltage from the bootstrap node according to a control voltage, wherein the active diode is a normally-ON transistor, wherein, when the floating reference node is coupled to the ground, the normally-ON transistor determines a forward current flowing from the supply voltage to the capacitor according to the control voltage, such that the capacitor stores a voltage difference, wherein, when the input voltage is applied to the floating reference node, the normally-ON transistor further isolates the supply voltage from the bootstrap node according to the control voltage,
wherein with the control voltage increasing, the forward current flowing from the supply voltage to the bootstrap node through the active diode is increasing accordingly.

2. The switch-mode converter of claim 1 , further comprising:
a control logic, supplied by the supply voltage and generating a high-side driving signal and a low-side driving signal to the high-side driver and the low-side driver respectively, according to an input signal.

3. The switch-mode converter of claim 1 , wherein the active diode is an N-type depletion transistor.

4. The switch-mode converter of claim 1 , wherein the active diode is a P-type depletion transistor.

5. The switch-mode converter of claim 1 , wherein the active diode is an N-type junction field-effect transistor.

6. The switch-mode converter of claim 1 , wherein the active diode is a P-type junction field-effect transistor.

7. The switch-mode converter of claim 2 , wherein the high-side driver further comprises:
a first P-type transistor, the source terminal coupled to the bootstrap node, the drain terminal generating the high-side output signal, and the gate terminal receiving the high-side driving signal; and
a first N-type transistor, the source terminal coupled to the floating reference node, the drain terminal generating the high-side output signal, and the gate terminal receiving the high-side driving signal.

8. The switch-mode converter of claim 2 , wherein the low-side driver further comprises:
a second P-type transistor, the source terminal supplied by the supply voltage, the drain terminal generating the low-side output signal, and the gate terminal receiving the low-side driving signal; and
a second N-type transistor, the source terminal coupled to the ground, the drain terminal generating the low-side output signal, and the gate terminal receiving the low-side driving signal.

9. A boost device, comprising:
a capacitor, coupled between a bootstrap node and a floating reference node, wherein the floating reference node alternately receives reference voltage of a ground and an input voltage; and
an active diode, providing a supply voltage to the bootstrap node and isolating the bootstrap node from the supply voltage according to a control voltage, wherein the supply voltage is less than the input voltage, and the supply voltage exceeds the reference voltage, wherein the active diode is a normally-ON transistor, wherein, when the floating reference node is supplied by the reference voltage, the normally-ON transistor provides the supply voltage to the bootstrap node for charging the capacitor, wherein, when the floating reference node is supplied by the input voltage, the normally-ON transistor isolates the supply voltage from the bootstrap node according to the control voltage,
wherein with the control voltage increasing, the forward current flowing from the supply voltage to the bootstrap node through the active diode is increasing accordingly.

10. The boost device of claim 9 , wherein, when the floating reference node is supplied by the reference voltage, the normally-ON transistor determines a forward current flowing from the supply voltage to the capacitor according to the control voltage, such that the capacitor stores a voltage difference, wherein, when the floating reference node is supplied by the input voltage, a voltage of the bootstrap node is a sum of the input voltage and the voltage difference, and the normally-ON transistor further isolates, according to the control voltage, the supply voltage from the bootstrap node to prevent the capacitor from discharging to the supply voltage, wherein the voltage difference is the supply voltage minus the reference voltage.

11. The boost device of claim 9 , wherein the active diode is an N-type depletion transistor.

12. The boost device of claim 9 , wherein the active diode is a P-type depletion transistor.

13. The boost device of claim 9 , wherein the active diode is an N-type junction field-effect transistor.

14. The boost device of claim 9 , wherein the active diode is a P-type junction field-effect transistor.

Assignees

• Vanguard Int Semiconduct Corp

Inventors

• Chin Yu-Lung
• Lin Shin-Cheng
• Lin Wen-Hsin
• Ho Yu-Hao

Classifications

• G05F1/61

  including two stages of regulation, at least one of which is output level responsive · CPC title

• G05F1/62

  using bucking or boosting DC sources · CPC title

• H02M3/1582

  Buck-boost converters (H02M3/1584 takes precedence) · CPC title

• H02M3/1588

  comprising at least one synchronous rectifier element (H02M3/1582, H02M3/1584 take precedence) · CPC title

• H02M1/08 Primary

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