Semiconductor equipment

Abstract

The aim is to reduce switching losses. [Solution] The semiconductor device 1 includes a switching circuit 1a and a lower arm control circuit 1b which includes a first circuit 1b1 and a second circuit 1b2. The switching circuit 1a includes a lower arm switching element 1a2 and is connected to a load M to operate the load M by switching drive. The first circuit 1b1 sets the reference potential to the ground potential Vgp and generates and outputs a first drive signal s1 from the received lower arm drive signal s0. The second circuit 1b2 sets the reference potential to a floating potential Vfp separated from the ground potential Vgp and generates a second drive signal s1n by inverting the level of the first drive signal s1n, and performs switching drive of the lower arm switching element 1a2 based on the second drive signal s1n.

Claims

1. A switching circuit including a lower arm switching element, which is connected to a load and operates the load by switching drive, A lower arm control circuit includes: a first circuit that receives a lower arm drive signal transmitted from a control unit with the ground potential as the reference potential, generates a first drive signal from the lower arm drive signal and outputs it; and a second circuit that generates a second drive signal by inverting the level of the first drive signal with the floating potential separated from the ground potential as the reference potential, and performs switching drive of the lower arm switching element based on the second drive signal; Semiconductor device.

2. The semiconductor device according to claim 1, wherein one end of a resistive element is connected to the low-potential side electrode of the lower arm switching element, and the other end of the resistive element is grounded.

3. The semiconductor device according to claim 2, wherein the floating potential is the potential generated at the low-potential side electrode of the lower arm switching element.

4. The semiconductor device according to claim 3, wherein when the upper arm switching element included in the switching circuit is turned off, the lower arm control circuit reduces the voltage between the control electrode and the low-potential side electrode of the lower arm switching element to turn off the lower arm switching element, and the potential of the control electrode and the potential of the low-potential side electrode are linked to keep the potential difference between the control electrode and the low-potential side electrode within a predetermined range.

5. The semiconductor device according to claim 1, wherein the first circuit generates the first drive signal by level-shifting the first voltage level of the lower arm drive signal to a second voltage level higher than the first voltage level.

6. The semiconductor device according to claim 5, wherein the first circuit includes a first inverter circuit that uses the ground potential as the reference potential, and the second circuit includes a second inverter circuit that uses the stray potential as the reference potential.

7. The semiconductor device according to claim 6, wherein the first circuit includes an odd number of first inverter circuits connected in series, and the second circuit includes an odd number of second inverter circuits connected in series.

8. The switching circuit further includes an upper arm switching element, an upper arm freewheeling diode, and a lower arm freewheeling diode, the first circuit includes a single first inverter circuit that references the ground potential via a first reference potential terminal, and the second circuit includes a single second inverter circuit that references the floating potential via a second reference potential terminal, and further comprises a resistive element, The floating potential is the potential generated at the lower arm low-potential side electrode of the lower arm switching element, The upper arm high-potential side electrode of the upper arm switching element is connected to the cathode of the upper arm freewheeling diode and a power supply voltage is applied to it. The upper arm low-potential side electrode of the upper arm switching element is connected to the anode of the upper arm freewheel diode, the load, the lower arm high-potential side electrode of the lower arm switching element, and the cathode of the lower arm freewheel diode. The first inverter circuit generates and outputs the first drive signal from the lower arm drive signal, the second inverter circuit generates the second drive signal by inverting the level of the first drive signal, and the second drive signal is output from the output terminal of the second inverter circuit. The control electrode of the lower arm switching element is connected to the output terminal of the second inverter circuit. The lower arm low-potential side electrode of the lower arm switching element is connected to the anode of the lower arm freewheeling diode, one end of the resistive element, and the second reference potential terminal of the second inverter circuit, and the other end of the resistive element is connected to the first reference potential terminal of the first inverter circuit. The semiconductor device according to claim 1.

9. The semiconductor device according to claim 8, wherein the lower arm control circuit is formed on an N-type substrate, the first reference potential terminal of the first circuit is formed on a first P-well formed on the surface of the N-type substrate, and the second reference potential terminal of the second circuit is formed on a second P-well formed on the surface of the N-type substrate and separated from the first P-well.

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