DRIVING CIRCUIT FOR SWITCHING ELEMENTS

• US 20080315938A1
• Filed: 09/04/2008
• Published: 12/25/2008
• Est. Priority Date: 06/30/2005
• Status: Active Grant

• Current Assignee: Hideki Miyazaki, Katsumi Ishikawa, Katsunori Suzuki, Koichi Suda
• Original Assignee: Hideki Miyazaki, Katsumi Ishikawa, Katsunori Suzuki, Koichi Suda
• Inventors: Ishikawa, Katsumi, Miyazaki, Hideki, Suzuki, Katsunori, Suda, Koichi
• Granted Patent: US 7,696,650 B2
• Time in Patent Office: Days
• US Class Current: 327/333
• CPC Class Codes: H03K 17/567 Circuits characterised by the use of more than one type of semiconductor device, e.g. BIMOS, composite devices such as IGBT

Abstract

A level shifting circuit, satisfying a requirement of a high tolerated dV/dt level, and a highly reliable inverter circuit, wherein a set pulse signal and a reset pulse signal, both of which are level-shifted to a potential side taking as reference a reference potential of a gate control terminal of a switching terminal, are obtained differentially and integrated, and, in case these pulse signals equal or exceed stipulated integrated values, are transmitted as regular control signals controlling the on/off state.

Claims

1. A drive circuit for switching devices, comprising:

a first and a second switching device connected in series between terminals of a main power supply;

a first control power supply which takes as reference potential a ground potential of said first switching device;

a second control power supply which takes as reference potential the potential of a connection point of said first and second switching devices;

a pulse generator which takes as reference potential the ground potential of said first switching device and generating a set pulse signal and a reset pulse signal; and

a level shifting circuit which level-shifts the set pulse signal and the reset pulse signal to the potential side taking as reference potential the potential of the connection point of said first and second switching devices, supplies the set pulse signal and the reset pulse signal to a flip-flop circuit, and controls on/off state of said second switching device;

wherein said level shifting device comprises comparator circuits outputting a difference of the set pulse signal and the reset pulse signal, both level shifted to the potential side taking as reference potential the potential of the connection point of said first and second switching devices, and, when the difference equals or exceeds a setting value, transmits the signals as regular signals to the gate of said second switching devices.

2. A drive circuit in accordance with claim 1, wherein said level shifting device comprises level shifting circuits for a set pulse signal and a reset pulse signal, to which switching devices and resistances are respectively connected in series, and said comparator circuits input the potential of the connection points of the switching devices and the resistances of said level shifting circuits.

3. A drive circuit for switching devices, comprising:

a first and a second switching device connected in series between terminals of a main power supply;

a first control power supply taking as reference potential a ground potential of said first switching device;

a second control power supply taking as reference potential of a connection point of said first and second switching devices;

a pulse generator taking as reference potential the ground potential of said first switching device and generating a set pulse signal and a reset pulse signal; and

a level shifting circuit level-shifting the set pulse signal and the reset pulse signal to the potential side taking as reference potential the potential of the connection point of said first and second switching devices, supplying the set pulse signal and the reset pulse signal to a flip-flop circuit, and controlling on/off state of said second switching device;

wherein said level shifting device comprises differential amplifier circuits outputting a difference of the set pulse signal and the reset pulse signal, both level shifted to the potential side taking as reference potential the potential of the connection point of said first and second switching devices, and comparator circuits which, when the difference equals or exceeds a setting value, transmit the signals as regular signals to the gate of said second switching device.

4. A drive circuit in accordance with claim 3, wherein said level shifting device comprises level shifting circuits for a set pulse signal and a reset pulse signal, to which switching devices and resistances are respectively connected in series, and the difference circuits take as input the potential of the connection points of the switching elements and the resistances of said level shifting circuits.

5. A semiconductor device driving a first semiconductor switching device and a second semiconductor switching device, both of which are connected in series between terminals of a main power supply, wherein said semiconductor device comprises:

a first control power supply taking as reference a ground potential of said first semiconductor switching device;

a second control power supply taking as reference a potential of said series connection point;

a pulse generator taking as reference the ground potential of said first semiconductor switching device and generating a first pulse signal and a second pulse signal;

a level shifter inputting said pulse signals, level-shifting the potential to the potential side taking as reference the potential of the series connection point, supplying the pulse signal to a flip-flop circuit, and driving said second semiconductor switching element; and

a comparator inputting the first and second pulse signals, level-shifted by said level shifter to the potential side taking as reference the potential of the series connection point, and outputting a difference of the first pulse signal and the second pulse signal;

and wherein said semiconductor device transmits, in case the difference output by said comparator is greater than a setting value, a drive signal to said second semiconductor switching device.

6. A semiconductor device in accordance with claim 5, wherein said pulse generator, level shifter, and comparator are formed on the same semiconductor substrate.

7. A semiconductor device in accordance with claim 6, wherein said first semiconductor switching device and second semiconductor switching device are also formed on the semiconductor substrate.