MOSFET drive circuit, programmable power supply and semiconductor test apparatus
View Patent ↗In a programmable power supply used in a semiconductor test apparatus, high-speed switching of a large current in a current rage or an output relay is enabled. In a MOSFET drive circuit 22 of a switch portion 20 provided in a programmable power supply 10 of a semiconductor test apparatus 1 , a capacitor portion 22 - 12 is charged with electric charges by a current from a light receiving portion 22 - 12 of a light insulating element 22 - 1 . When an SWA is turned on (SWB is turned off) by changeover of the analog switch portion 22 - 3 , a gate of each MOSFET in the MOSFET portion 21 is charged with the electric charges stored in the capacitor portion 22 - 12 , and enters an ON state. On the other hand, when the SWB of the analog switch portion 22 - 3 is turned on (SWA is turned off), the gate of the MOSFET is discharged.
1. A MOSFET drive circuit which drives a MOSFET, comprising:
a capacitor which stores electric charges for charging a gate of the MOSFET;
a first analog switch which changes over whether the gate of the MOSFET is charged with the electric charges stored in the capacitor; and
a second analog switch which changes over whether the gate of the MOSFET is discharged by short-circuiting the gate and a source of the MOSFET.
2. The MOSFET drive circuit according to claim 1 , further comprising:
a light insulating element having a light receiving portion which emits light beams upon receiving an input signal, and
a light receiving portion which supplies a current to the capacitor upon receiving the light beams from the light emitting portion.
3. The MOSFET drive circuit according to claim 1 , further comprising a charge auxiliary circuit which subserves charging of the capacitor.
4. A MOSFET drive circuit which drives a MOSFET, comprising:
an analog switch which changes over whether a gate of the MOSFET is discharged by short-circuiting the gate and a source of the MOSFET.
5. A programmable power supply which can measure a current flowing through a load as a power supply target and switch a range according to a value of the current, comprising:
a flow dividing circuit which comprises in accordance with the range one or more flow dividing branch circuits each of which includes a resistor and a MOSFET, the respective flow dividing branch circuits being connected with each other in parallel; and
a MOSFET drive circuit which individually drives the MOSFETs included in the flow dividing circuit,
wherein the MOSFET drive circuit comprises the MOSFET drive circuit which is comprised of:
a capacitor which stores electric charges for charging a gate of the MOSFET;
a first analog switch which changes over whether the gate of the MOSFET is charged with the electric charges stored in the capacitor; and
a second analog switch which changes over whether the gate of the MOSFET is discharged by short-circuiting the gate and a source of the MOSFET.
6. A semiconductor test apparatus comprising:
a programmable power supply which supplies a power to a device under test and measures a current flowing through the device under test, wherein the programmable power supply comprises:
a flow dividing circuit which comprises in accordance with the range one or more flow dividing branch circuits each of which includes a resistor and a MOSFET, the respective flow dividing branch circuits being connected with each other in parallel; and
a MOSFET drive circuit which individually drives the MOSFETs included in the flow dividing circuit,
wherein the MOSFET drive circuit comprises the MOSFET drive circuit which is comprised of:
a capacitor which stores electric charges for charging a gate of the MOSFET;
a first analog switch which changes over whether the gate of the MOSFET is charged with the electric charges stored in the capacitor; and
a second analog switch which changes over whether the gate of the MOSFET is discharged by short-circuiting the gate and a source of the MOSFET.