Semiconductor device, motor drive control device, and motor unit

Patent metadata

Field	Value
Publication number	US-11336291-B2
Application number	US-202016775425-A
Country	US
Kind code	B2
Filing date	Jan 29, 2020
Priority date	Feb 1, 2019
Publication date	May 17, 2022
Grant date	May 17, 2022

Abstract

A semiconductor device has an A/D converter configured to convert an analog signal representing a current flowing in a control target into a digital signal, an overcurrent determination unit configured to, based on the analog signal, determine that an overcurrent has occurred in the control target when the current flowing in the control target has exceeded an overcurrent threshold, and determine that the overcurrent has not occurred in the control target when the current flowing in the control target has not exceeded the overcurrent threshold, a drive control signal generation unit configured to generate a drive control signal for controlling driving of the control target so that the current flowing in the control target is equal to a target current, based on a conversion result of the A/D converter, and generate the drive control signal to reduce the current flowing in the control target when the overcurrent determination unit determines that the overcurrent has occurred, and an overcurrent threshold setting unit configured to set the overcurrent threshold based on the conversion result of the A/D converter and the target current.

First claim

What is claimed is:

1. A semiconductor device, comprising:
an A/D converter configured to convert an analog signal representing a current flowing in a control target into a digital signal;
an overcurrent determination unit configured to, based on the analog signal, determine that an overcurrent has occurred in the control target when the current flowing in the control target has exceeded an overcurrent threshold, and determine that the overcurrent has not occurred in the control target when the current flowing in the control target has not exceeded the overcurrent threshold;
a drive control signal generation unit configured to generate a drive control signal for controlling driving of the control target so that the current flowing in the control target is equal to a target current, based on a conversion result of the A/D converter, and generate the drive control signal to reduce the current flowing in the control target when the overcurrent determination unit determines that the overcurrent has occurred; and
an overcurrent threshold setting unit configured to set the overcurrent threshold based on the conversion result of the A/D converter and the target current.

2. The semiconductor device according to claim 1 , wherein
the overcurrent threshold setting unit reduces the overcurrent threshold when the conversion result of the A/D converter is larger than the target current, and increases the overcurrent threshold when the conversion result of the A/D converter is smaller than the target current.

3. The semiconductor device according to claim 2 , wherein
the overcurrent threshold setting unit reduces the overcurrent threshold when the conversion result of the A/D converter is larger than a predetermined current range taking the target current as a reference, increases the overcurrent threshold when the conversion result of the A/D converter is smaller than the predetermined current range, and sets the overcurrent threshold based on a determination result by the overcurrent determination unit when the conversion result of the A/D converter is in the predetermined current range.

4. The semiconductor device according to claim 3 , wherein
an adjustment amount of the overcurrent threshold when the conversion result of the A/D converter is in the predetermined current range is smaller than an adjustment amount of the overcurrent threshold when the conversion result of the A/D converter is out of the predetermined current range.

5. The semiconductor device according to claim 3 , wherein
the overcurrent threshold setting unit increases the overcurrent threshold in the event that the overcurrent determination unit determines that the overcurrent has occurred when the conversion result of the A/D converter is in the predetermined current range.

6. The semiconductor device according to claim 5 , wherein
the overcurrent threshold setting unit determines whether the overcurrent threshold has been changed, based on an occurrence history of the overcurrent in the event that the overcurrent determination unit determines that the overcurrent has not occurred when the conversion result of the A/D converter is in the predetermined current range.

7. The semiconductor device according to claim 1 , wherein
the overcurrent threshold setting unit changes an initial value of the overcurrent threshold in response to the change of the target current, and changes the overcurrent threshold from the initial value based on a relative magnitude of the conversion result of the A/D converter with respect to the target current.

8. A motor drive control device, comprising:
the semiconductor device according to claim 1 ;
a current detection circuit configured to output a voltage corresponding to a current flowing in a motor serving as a control target; and
a motor drive unit configured to drive the motor based on the drive control signal generated by the semiconductor device,
wherein the semiconductor device inputs a voltage output from the current detection circuit as the analog signal.

9. A motor unit, comprising:
the motor drive control device according to claim 8 ; and
the motor.

Assignees

• Minebea Mitsumi Inc

Inventors

• Aoki Masato

Classifications

• H02M1/082

  with digital control · CPC title

• H03M3/00 Primary

  Conversion of analogue values to or from differential modulation · CPC title

• H02M1/0012

  Control circuits using digital or numerical techniques (in DC/DC converters H02M3/157, H02M3/33515; in DC-AC converters H02M7/53873) · CPC title

• H02M1/32

  Means for protecting converters other than automatic disconnection · CPC title

• H02M1/0009

  Devices or circuits for detecting current in a converter · CPC title