Driving circuit for switching element, and switching circuit
A switching element 1 has a gate terminal connected to an output end Vout of a driving circuit 12 via a capacitor 11 and a resistor 13 connected in parallel. The switching element 1 has a source terminal connected to the driving circuit 12 via a capacitor 14 and a Zener diode 15 connected in parallel. The Zener diode 15 has an anode terminal connected to the source terminal of the switching element 1 and a cathode terminal connected to the driving circuit 12.
1. A driving circuit for a switching element configured to drive a switching element of a current-driven type, the driving circuit for a switching element comprising:
a controller comprising a first terminal and a second terminal, the controller being configured to output a control signal to a gate terminal of the switching element;
a first resistor connected to the first terminal of the controller, the first resistor regulating a current serving as the control signal;
a first capacitor connected in parallel to the first resistor;
a second capacitor;
a first Zener diode connected in parallel to the second capacitor; and
a current path extending from the first resistor and the first capacitor to the gate terminal and from a source terminal of the switching element to the second terminal of the controller, wherein
the second capacitor and the first Zener diode are put in a path extending from the source terminal to the controller, and the first Zener diode comprises a cathode terminal connected to the second terminal of the controller and an anode terminal connected to the source terminal, and
when a capacitance of the first capacitor is denoted by C1, a capacitance of the second capacitor is denoted by C2, an input capacitance of the switching element is denoted by Ciss, a source voltage of the control signal is denoted by Vdd, a gate-source voltage when the switching element is in a turn-on state is denoted by Vdev, and a negative bias voltage applied to the switching element is denoted by Vcc,
1
C
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s
s
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1
(
1
C
1
+
1
C
2
+
1
C
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s
s
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V
c
c
+
V
d
e
v
V
d
d
[
Math
.
1
]
is satisfied.
2. The driving circuit for a switching element according to claim 1 , further comprising a mirror clamping circuit provided in parallel to a path comprising the switching element, the second capacitor, and the first Zener diode.
3. The driving circuit for a switching element according to claim 1 , further comprising a third capacitor connected between the gate terminal and the source terminal of the switching element.
4. The driving circuit for a switching element according to claim 1 , further comprising a third resistor connected to the path in series with the first capacitor and in parallel to the first resistor.
5. The driving circuit for a switching element according to claim 1 , further comprising a second Zener diode comprising a cathode terminal connected to a section adjacent to the gate terminal of the switching element and an anode terminal connected to a section adjacent to the source terminal of the switching element.
6. The driving circuit for a switching element according to claim 1 , further comprising a fourth resistor connected between the gate terminal and the source terminal of the switching element.
7. The driving circuit for a switching element according to claim 1 , further comprising a Schottky diode connected in parallel to a path comprising the switching element, the second capacitor, and the first Zener diode, the Schottky diode comprising a cathode terminal connected to a section adjacent to the source terminal of the switching element and an anode terminal connected to a section adjacent to the cathode terminal of the first Zener diode.
8. A switching circuit comprising:
a plurality of switching elements of a current-driven type connected in series; and
a driving circuit for a switching element configured to drive each of the plurality of switching elements,
the driving circuit for the switching element comprising:
a controller comprising a first terminal and a second terminal, the controller being configured to output a control signal to a gate terminal of the switching element;
a first resistor connected to the first terminal of the controller, the first resistor regulating a current serving as the control signal;
a first capacitor connected in parallel to the first resistor;
a second capacitor;
a first Zener diode connected in parallel to the second capacitor; and
a current path extending from the first resistor and the first capacitor to the gate terminal and from a source terminal of the switching element to the second terminal of the controller, wherein
the second capacitor and the first Zener diode are put in a path extending from the source terminal to the controller, and the first Zener diode comprises a cathode terminal connected to the second terminal of the controller and an anode terminal connected to the source terminal, and
when a capacitance of the first capacitor is denoted by C1, a capacitance of the second capacitor is denoted by C2, an input capacitance of the switching element is denoted by Ciss, a source voltage of the control signal is denoted by Vdd, a gate-source voltage when the switching element is in a turn-on state is denoted by Vdev, and a negative bias voltage applied to the switching element is denoted by Vcc,
1
Ciss
*
1
(
1
C
1
+
1
C
2
+
1
Ciss
)
<
Vcc
+
Vdev
Vdd
[
Math
.
1
]
is satisfied.