Switching element driving device

Patent metadata

Field	Value
Publication number	US-2018159526-A1
Application number	US-201615577796-A
Country	US
Kind code	A1
Filing date	Apr 26, 2016
Priority date	Jun 17, 2015
Publication date	Jun 7, 2018
Grant date	—

Abstract

A switching element driving device includes: a drive circuit that is connected between an element driving power supply and a circuit ground and outputs a driving signal to a driving switching element; a capacitor that is connected between the circuit ground and a reference ground to which a potential reference side conduction terminal of the driving switching element is connected; and a regulator that charges and discharges so that the capacitor has a predetermined terminal voltage. The regulator discharges the capacitor when the terminal voltage exceeds an upper limit value, and charges the capacitor when the terminal voltage falls below a lower limit value.

First claim

1 . A switching element driving device comprising:
a drive circuit that is connected between an element driving power supply and a circuit ground and outputs a driving signal to a driving switching element; a capacitor that is connected between the circuit ground and a reference ground, to which a potential reference side conduction terminal of the driving switching element is connected; and a regulator that charges and discharges the capacitor so as to keep a predetermined terminal voltage of the capacitor, wherein: the regulator discharges the capacitor when the terminal voltage exceeds an upper limit value, and charges the capacitor when the terminal voltage falls below a lower limit value.

2 . The switching element driving device according to claim 1 , wherein:
the regulator includes
a charger that charges the capacitor,
a discharger that discharges the capacitor,
a charge controller that controls the charger, and
a discharge controller that controls the discharger;
the charge controller causes the charger to operate when the terminal voltage falls below the lower limit value; and the discharge controller causes the discharger to operate when the terminal voltage exceeds the upper limit value.

3 . The switching element driving device according to claim 2 , wherein:
the charge controller and the discharge controller are configured by comparators.

4 . The switching element driving device according to claim 3 , wherein:
the comparators are comparators with a hysteresis.

5 . The switching element driving device according to claim 2 , wherein:
the charge controller and the discharge controller are configured by operational amplifiers.

6 . The switching element driving device according to claim 2 , wherein:
the charger and the discharger are configured by a series circuit including a positive switching element and a negative switching element, the series circuit being connected between the element driving power supply and the circuit ground; and a common connection point of the series circuit is connected to the reference ground.

7 . The switching element driving device according to claim 2 , wherein:
the charge controller is provided by a first energizing part having a first end connected to the element driving power supply, a first Zener diode having a cathode connected to a second end of the first energizing part, and a second Zener diode having an anode connected to an anode of the first Zener diode; the discharge controller is provided by a second energizing part having a first end connected to a cathode of the second Zener diode, and a third Zener diode having a cathode connected to a second end of the second energizing part and an anode connected to the circuit ground; the upper limit value is applied as a Zener voltage of the third Zener diode; and the lower limit value is applied as a voltage obtained by subtracting a sum of a Zener voltage of the first Zener diode and a forward voltage of the second Zener diode from a voltage of the element driving power supply.

8 . The switching element driving device according to claim 1 , wherein:
the upper limit value and the lower limit value are both generated by resistance voltage divider circuits connected between the element driving power supply and the circuit ground.

9 . The switching element driving device according to claim 1 , wherein:
the upper limit value and the lower limit value are both generated by a series circuit of energizing parts and Zener diodes, each being connected between the element driving power supply and the circuit ground.

10 . The switching element driving device according to claim 1 , further comprising:
a band gap reference circuit that is connected between the element driving power supply and the circuit ground; and resistance voltage divider circuits that divide an output voltage of the band gap reference circuit, wherein:
the upper limit value and the lower limit value are generated by the resistance voltage divider circuits.

Assignees

• Denso Corp

Inventors

• Inoue Norihiko
• Irie Masashi

Classifications

• H03K2017/226

  in bipolar transistor switches · CPC title

• H03K17/567

  Circuits characterised by the use of more than one type of semiconductor device, e.g. BIMOS, composite devices such as IGBT · CPC title

• H03K17/22 Primary

  Modifications for ensuring a predetermined initial state when the supply voltage has been applied (bi-stable generators H03K3/12) · CPC title

• H03K2217/0081

  Power supply means, e.g. to the switch driver · CPC title

• H03K2017/066

  Maximizing the OFF-resistance instead of minimizing the ON-resistance · CPC title