DRIVE CIRCUIT FOR SWITCH
First Claim
1. A drive circuit (Dr) for a switch, the drive circuit driving a switch (SW, SWA, SWB), the drive circuit comprising:
- an acquisition section, which acquires a surge-correlated value, the surge-correlated value being one of an inter-terminal voltage (Von, VonA, VonB) of the switch while the switch is in an on state and a time period from when an on command for the switch is issued to when a gate voltage of the switch reaches a determination voltage (Vα
) that is less than an upper limit value (VH) and is larger than or equal to a Miller voltage (Vmil); and
a setting section, wherein, when the acquired surge-correlated value is larger, the setting section sets a switching speed of the switch when the switch is switched to an off state to be lower than the switching speed of the switch when the acquired surge-correlated value is small.
1 Assignment
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Accused Products
Abstract
A drive circuit Dr for a switch that reduces a surge voltage caused when a switch SW is switched to an off state. The drive circuit Dr detects, as an on voltage Von, a collector-emitter voltage of the switch SW while the switch SW is in an on state. When the detected on voltage Von is large, the drive circuit Dr sets a resistance value Rd of a discharging resistor 53 when the switch SW is switched to an off state to be larger than the resistance value Rd when the detected on voltage Von is small. More specifically, the drive circuit Dr sets the resistance value Rd to a larger value as the detected on voltage Von is increased.
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Citations
9 Claims
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1. A drive circuit (Dr) for a switch, the drive circuit driving a switch (SW, SWA, SWB), the drive circuit comprising:
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an acquisition section, which acquires a surge-correlated value, the surge-correlated value being one of an inter-terminal voltage (Von, VonA, VonB) of the switch while the switch is in an on state and a time period from when an on command for the switch is issued to when a gate voltage of the switch reaches a determination voltage (Vα
) that is less than an upper limit value (VH) and is larger than or equal to a Miller voltage (Vmil); anda setting section, wherein, when the acquired surge-correlated value is larger, the setting section sets a switching speed of the switch when the switch is switched to an off state to be lower than the switching speed of the switch when the acquired surge-correlated value is small. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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Specification