Bootstrap compensation circuit and power module

• US 9,755,548 B2
• Filed: 04/15/2016
• Issued: 09/05/2017
• Est. Priority Date: 09/09/2015
• Status: Active Grant

• Current Assignee: Mitsubishi Electric Corporation
• Original Assignee: Mitsubishi Electric Corporation
• Inventors: Yoshida, Hiroshi, Oyama, Kyoko
• Primary Examiner(s): Dole, Timothy J
• Assistant Examiner(s): AHMED, YUSEF A
• Application Number:
  US15/130,164
• Publication Number:
  US 20170070220A1
• Time in Patent Office: 508 Days
• CPC Class Codes: H02M 7/5387 in a bridge configuration
• CPC Class Codes: H03K 17/063 in field-effect transistor switches
• CPC Class Codes: H03K 17/691 using transformer coupling
• CPC Class Codes: H03K 2217/0063 High side switches, i.e. the higher potential [DC] or life wire [AC] being directly connected to the switch and not via the load
• CPC Class Codes: H03K 2217/0072 Low side switches, i.e. the lower potential [DC] or neutral wire [AC] being directly connected to the switch and not via the load
• CPC Class Codes: H03K 2217/0081 Power supply means, e.g. to the switch driver

Abstract

A bootstrap compensation circuit includes: a plurality of resistors series-connected between a floating potential corresponding to a high-voltage-side potential and a reference potential; a second capacitor that has one end connected to a divided potential extraction point and has the other end connected to the reference potential, the divided potential extraction point located between the plurality of resistors; and an output circuit which supplies current to a first capacitor, according to a potential of the divided potential extraction point.

Claims

1. A bootstrap compensation circuit which supplies current to a bootstrap circuit, said bootstrap circuit including a first capacitor connected between a reference potential, which is a connection point between a high-side switching element and a low-side switching element, and each of a high-side control circuit and a low-side control circuit, respectively, where the switching elements are totem-pole connected between a high-voltage-side potential and a low-voltage-side potential, said bootstrap compensation circuit comprising:

a plurality of resistors series-connected between a floating potential corresponding to said high-voltage-side potential and said reference potential;

a second capacitor, one end of which is connected to a divided potential extraction point and the other end of which is connected to said reference potential, the divided potential extraction point being a point between said plurality of resistors; and

an output circuit which supplies current to said first capacitor, based on a potential of said divided potential extraction point.

2. The bootstrap compensation circuit according to claim 1, further comprising a diode whose cathode is connected to said floating potential and whose anode is connected to said divided potential extraction point.

3. The bootstrap compensation circuit according to claim 1, further comprising a Zener diode whose cathode is connected to said floating potential and whose anode is connected to said divided potential extraction point.

4. A power module comprising:

the bootstrap compensation circuit according to claim 1;

said high-side switching element;

said low-side switching element;

said high-side control circuit;

said low-side control circuit; and

said bootstrap circuit.

5. A bootstrap compensation circuit which supplies current to a bootstrap circuit, said bootstrap circuit including a capacitor connected between a reference potential, which is a connection point between a high-side switching element and a low-side switching element, and each of a high-side control circuit and a low-side control circuit, respectively, where the switching elements are totem-pole connected between a high-voltage-side potential and a low-voltage-side potential, said bootstrap compensation circuit comprising:

a plurality of first resistors series-connected between a floating potential corresponding to said high-voltage-side potential and said reference potential;

a first MOSFET whose drain is connected to a divided potential extraction point and whose source and gate are connected to said reference potential, the divided potential extraction point being a point between said plurality of first resistors; and

an output circuit which supplies current to said capacitor, based on a potential of said divided potential extraction point.

6. The bootstrap compensation circuit according to claim 5, further comprising:

a second resistor, one end of which is connected to said floating potential;

a second MOSFET whose drain is connected to the other end of said second resistor; and

a third MOSFET whose drain is connected to a source of said second MOSFET and whose source is connected to said reference potential,

wherein the gate of said first MOSFET, a gate of said second MOSFET, and a gate of said third MOSFET are connected to one another, and

the gate of said second MOSFET and a source of said second MOSFET are connected to each other.

7. The bootstrap compensation circuit according to claim 5, further comprising a diode whose cathode is connected to said floating potential and whose anode is connected to said divided potential extraction point.

8. The bootstrap compensation circuit according to claim 5, further comprising a Zener diode whose cathode is connected to said floating potential and whose anode is connected to said divided potential extraction point.

9. A power module comprising:

the bootstrap compensation circuit according to claim 5;

said high-side switching element;

said low-side switching element;

said high-side control circuit;

said low-side control circuit; and

said bootstrap circuit.