CN-122026697-A - Semiconductor device with a semiconductor device having a plurality of semiconductor chips

Abstract

Provided is a semiconductor device which can suppress unexpected application of a control power supply voltage drop protection during initial charging and can perform the control power supply voltage drop protection even during stabilization of the control power supply voltage. A semiconductor device (100) according to an embodiment is provided with an IGBT (41), a control IC (1), a control IC (2A), and a bootstrap circuit (3), wherein the bootstrap circuit (3) generates a control power supply voltage VccU supplied to the control IC (1) by a bootstrap operation using a control power supply voltage VccL supplied to the control IC (2A), the control IC (2A) is provided with a control voltage detection circuit (22A) for detecting a decrease in the control power supply voltage VccL, and the control voltage detection circuit (22A) is provided with a period detection circuit (221A) for detecting an initial charging period in which the bootstrap circuit (3) is initially charged by an automatic operation.

Inventors

• MINAGAWA TAKASHI

Assignees

• 富士电机株式会社

Dates

Publication Date

20260512

Application Date

20250904

Priority Date

20241112

Claims (8)

1. 1. A semiconductor device is provided with: A first switching element; A second switching element connected in series with the first switching element and disposed at a position on a lower potential side than the first switching element; A first control circuit that controls a driving operation of the first switching element; A second control circuit for controlling the driving operation of the second switching element and the protection operation of the first switching element and the second switching element, and A bootstrap circuit that generates a first control power supply voltage supplied to the first control circuit by a bootstrap action using a second control power supply voltage supplied to the second control circuit, Wherein the second control circuit has a voltage reduction detection circuit that detects a reduction in the second control power supply voltage, The voltage drop detection circuit has a period detection circuit that detects an initial charging period during which the bootstrap circuit is initially charged by the self-behavior.
2. 2. The semiconductor device according to claim 1, wherein, The voltage drop detection circuit has a voltage conversion circuit that increases a determination voltage for determining a drop in the second control power supply voltage after the period detection circuit detects the end of the initial charging period, as compared with before the period detection circuit detects the end of the initial charging period.
3. 3. The semiconductor device according to claim 2, wherein, The voltage conversion circuit sets the determination voltage to 0 volt during the initial charging period.
4. 4. The semiconductor device according to any one of claim 1 to 3, wherein, The period detection circuit detects the initial charging period based on a difference between a charging voltage, which is a voltage based on a charging current flowing through the bootstrap circuit at the time of the bootstrap operation, and a comparison voltage having the same voltage level as the second control power supply voltage.
5. 5. The semiconductor device according to any one of claim 1 to 3, wherein, The period detection circuit detects the initial charging period based on a charging voltage, which is a voltage based on a charging current flowing through the bootstrap circuit at the time of the bootstrap operation.
6. 6. The semiconductor device according to claim 2, wherein, The voltage drop detection circuit includes a delay circuit that delays a presentation signal input from the period detection circuit, the presentation signal indicating that the end of the initial charging period is detected, by a predetermined time, and outputs the delayed presentation signal to the voltage conversion circuit.
7. 7. The semiconductor device according to claim 2, wherein, The period detection circuit includes a delay circuit that delays a charge start signal indicating that the initial charge of the bootstrap circuit is started by a predetermined time to output the charge start signal to the voltage conversion circuit as a presentation signal indicating that the end of the initial charge period is detected.
8. 8. The semiconductor device according to claim 1, wherein, The voltage drop detection circuit includes: an output terminal for outputting an output signal indicating whether the second control power supply voltage is lowered by a voltage level, and And a fixing circuit that fixes a voltage level of the output terminal to a voltage level at which the output signal does not indicate a decrease in the second control power supply voltage, before the end of the initial charging period is detected by the period detecting circuit.

Description

Semiconductor device with a semiconductor device having a plurality of semiconductor chips Technical Field The present disclosure relates to a semiconductor device. Background An intelligent power module (INTELLIGENT POWER MODULE: IPM) is known, which is obtained by integrating an insulated gate bipolar transistor (Insulated Gate Bipolar Transistor: IGBT) for power conversion, a flywheel Diode (FREE WHEELING Diode: FWD), and an integrated circuit (INTEGRATED CIRCUIT: IC) for driving a protection function into one package. In IPM used as a three-phase inverter circuit for driving a motor such as a three-phase motor, for example, 4 (3 for the upper arm and 1 for the lower arm) control voltages are required, but if a Bootstrap circuit having a Bootstrap Diode (BSD), a capacitor, and a limiting resistor is applied, the power supply of the upper arm can be replaced with the capacitor. This reduces the component mounting area of the power conversion device including the IPM. The bootstrap circuit needs to charge (initially charge) the capacitor by the switching operation of the IGBT of the lower arm before the IGBT starts driving the load device such as the motor. At the time of initial charging, a current (surge current) flows from the control power supply for the lower arm to the bootstrap circuit. If the inrush current is an excessive current as described above, the ability of the lower arm to control the power supply may be insufficient, and power supply reduction protection may be applied to the lower arm. The bootstrap circuit has a limiting resistance as described above to suppress this power supply reduction protection. Patent document 1 discloses a power conversion device capable of suppressing an excessive surge current from flowing to a capacitor due to an abnormality of a switch of an initial charging circuit, and detecting an abnormal state of the switch of the initial charging circuit. Patent document 2 discloses an invention for reducing a surge current by determining a timing to delay completion of initial charging based on a magnitude of a current generated by initial charging when a plurality of capacitors are initially charged in a power converter. Prior art literature Patent literature Patent document 1 Japanese patent application laid-open No. 2022-40631 Patent document 2 Japanese patent application laid-open No. 2023-162789 Disclosure of Invention Problems to be solved by the invention In the control power supply voltage drop protection of the related art, an operation voltage level is designed so as to protect against a voltage drop with reference to when the control power supply voltage is stabilized. Therefore, in an operation in which voltage fluctuation is large, such as in the initial charging period, the control power supply voltage drop protection is easy to operate. If the power supply reduction protection is applied to the lower arm, the capacitor of the bootstrap circuit is not charged, and thus there is a problem in that the control power supply voltage of the upper arm does not reach a desired voltage level. On the other hand, if the operating voltage for controlling the power supply voltage drop protection is set based on the voltage fluctuation during the initial charging period, there is a problem that the protection operation is insufficient when the control power supply voltage is stabilized at a desired voltage level. An object of the present disclosure is to provide a semiconductor device capable of suppressing unexpected application of a drop protection of a control power supply voltage during initial charging and capable of performing the drop protection of the control power supply voltage even during stabilization of the control power supply voltage. Solution for solving the problem In order to achieve the above object, a semiconductor device according to one embodiment of the present disclosure includes a first switching element, a second switching element connected in series with the first switching element and arranged at a position on a lower potential side than the first switching element, a first control circuit that controls a driving operation of the first switching element, a second control circuit that controls the driving operation of the second switching element and a protection operation of the first switching element and the second switching element, and a bootstrap circuit that generates a first control power supply voltage supplied to the first control circuit by a bootstrap operation using a second control power supply voltage supplied to the second control circuit, wherein the second control circuit has a voltage drop detection circuit that detects a drop in the second control power supply voltage, and the voltage drop detection circuit has a period detection circuit that detects an initial charging period during which the initial charging of the bootstrap circuit is performed by the self-operation. ADVANTAGEOUS EFFECTS OF INVENTION According to one a