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US 5,963,066 AGranted
Semiconductor device which drives low-voltage driven switching device, using low-voltage direct current power source, a diode and a capacitor
AssigneeMitsubishi Denki Kabushiki Kaisha
InventorMasanori Fukunaga
Life of this patent
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Abstract
A capacitor (C) and a Zener diode (ZD2) are connected in parallel to a high-voltage side drive circuit (2). when a Zener voltage (VZD2) is set 5V, a voltage which is charged up in the capacitor (C) is determined by the Zener voltage (VZD2). Hence, it is only necessarv to set a voltage (VCC) in a loxv-voltage d.c. power source (4) at a value which is higher than (VZD2+VD+VCE), where VD is a forward-direction voltage to a diode (Di) and VCE is an ON-voltage to a low-voltage side switching device (Q1). Since a variation in a charging voltage which is supplied to a high-voltage side drive circuit is suppressed, it is possible to drive a switching device with 5V.
Claims20
A semiconductor device, comprising:
- a high-voltage direct current power source;
- a high-voltage side switching device whose first electrode is connected to said high-voltage direct current power source;
- a high-voltage side drive circuit whose first terminal and second terminal are respectively connected to a control electrode and a second electrode of said high-voltage side switching device;
- a low-voltage side switching device whose first electrode is connected to said second electrode of said high-voltage side switching device, a second electrode of said low-voltage side switching device being connected to a ground;
- and
- a low-voltage side drive circuit whose first terminal and second terminal are respectively connected to a control electrode and said second electrode of said low-voltage side switching device,
- wherein said high-voltage side switching device and said low-voltage side switching device are controlled by said high-voltage side drive circuit and said low-voltage side drive circuit to alternatively turn on and off, and
- said semiconductor device further comprises:
- a diode;
- a low-voltage direct current power source whose one end and other end are respectively connected to an anode of said diode and said ground;
- a capacitor whose first electrode is connected to said one end of said low-voltage direct current power source through said diode and also to a third terminal of said high-voltage side drive circuit, a second electrode of said capacitor being connected to said second electrode of said high-voltage side switching device;
- and
- a voltage fixing circuit connected in parallel to said capacitor for fixing a voltage value between the both ends of said capacitor during charging of said capacitor which occurs while said high-voltage side switching device operates in an on-state.
10 more elements
A semiconductor device, comprising:
- a high-voltage side switching device whose first electrode is connected to a high-voltage direct current power source;
- a high-voltage side drive circuit whose first terminal and second terminal are respectively connected to a control electrode and a second electrode of said high-voltage side switching device;
- a low-voltage side switching device whose first electrode is connected to said second electrode of said high-voltage side switching device, a second electrode of said low-voltage side switching device being connected to a ground;
- and
- a low-voltage side drive circuit whose first terminal and second terminal are respectively connected to a control electrode and said second electrode of said low-voltage side switching device,
- wherein said high-voltage side switching device and said low-voltage side switching device are controlled by said high-voltage side drive circuit and said low-voltage side drive circuit to alternatively turn on and off, and
- said semiconductor device further comprises:
- a low-voltage side diode whose cathode and anode are respectively connected to said first electrode and said second electrode of said low-voltage side switching device;
- a diode;
- a low-voltage direct current power source whose one end and other end are respectively connected to an anode of said diode and said ground;
- and
- a charging voltage supplying circuit which is connected to a cathode of said diode, said ground and a third terminal of said high-voltage side drive circuit, said charging voltage supplying circuit storing a charge which is supplied from said low-voltage direct current power source but not through said low-voltage side switching device nor said low-voltage side diode and which is needed to drive said high-voltage side switching device when said low-voltage side switching device operates in an on-state, said charging voltage supplying circuit supply ing a charging voltage which is in accordance with said charge to said high-voltage side drive circuit when said high-voltage side switching device operates in an on-state.
9 more elements
A semiconductor device, comprising:
- a high-voltage side switching device whose first electrode is connected to a high-voltage direct current power source;
- a high-voltage side drive circuit whose first terminal and second terminal are respectively connected to a control electrode and a second electrode of said high-voltage side switching device;
- a low-voltage side switching device whose first electrode is connected to said second electrode of said high-voltage side switching device, a second electrode of said low-voltage side switching device being connected to a ground;
- and
- a low-voltage side drive circuit whose first terminal and second terminal are respectively connected to a control electrode and said second electrode of said low-voltage side switching device,
- wherein said high-voltage side switching device and said low-voltage side switching device are controlled by said high-voltage side drive circuit and said low-voltage side drive circuit to alternatively turn on and off, and
- said semiconductor device further comprises:
- a low-voltage side diode whose cathode and anode are respectively connected to said first electrode and said second electrode of said low-voltage side switching device;
- a diode;
- a low-voltage direct current power source whose one end and other end are respectively connected to an anode of said diode and said ground;
- and
- a charging voltage supplying circuit which is connected to a cathode of said diode, said ground and a third terminal of said high-voltage side drive circuit, said charging voltage supplying circuit storing a charge which is supplied from said low-voltage direct current power source but not through said low-voltage side switching device nor said low-voltage side diode and which is needed to drive said high-voltage side switching device when said high-voltage side switching device operates in an on-state, said charging voltage supplying circuit supplying a charging voltage which is in accordance with said charge to said high-voltage side drive circuit when said low-voltage side switching device operates in an on-state.
9 more elements
Dependencies are inferred from the claim text.