Drive circuit and semiconductor apparatus

Patent metadata

Field	Value
Publication number	US-2017244352-A1
Application number	US-201615260632-A
Country	US
Kind code	A1
Filing date	Sep 9, 2016
Priority date	Feb 19, 2016
Publication date	Aug 24, 2017
Grant date	—

Abstract

According to embodiments, a drive circuit includes a control portion configured to, when a duty ratio is set to a first predetermined value, and a load apparatus is in an overload state, set the duty ratio to a second predetermined value smaller than the first predetermined value during a predetermined time period.

First claim

What is claimed is:

1 . A drive circuit comprising a control portion configured to, when a duty ratio is set to a first predetermined value, and a load apparatus is in an overload state, set the duty ratio to a second predetermined value smaller than the first predetermined value during a predetermined time period.

2 . The drive circuit according to claim 1 , comprising a limit signal generating portion; wherein
when a parameter value outputted from the load apparatus exceeds a predetermined threshold, the limit signal generating portion outputs a limit signal indicating that the load apparatus is in the overload state, to the control portion.

3 . The drive circuit according to claim 2 , wherein
the parameter value is a current value; and the limit signal generating portion is connected to a load apparatus driving portion configured to drive the load apparatus and acquires the current value from the load apparatus driving portion.

4 . The drive circuit according to claim 3 , wherein
when the duty ratio is set to the first predetermined value, and the limit signal is inputted from the limit signal generating portion, the control portion sets the duty ratio to the second predetermined value; and the control portion outputs an internal PWM signal based on the set duty ratio.

5 . The drive circuit according to claim 4 , wherein
the load apparatus is a motor; the load apparatus driving portion is a motor driving portion configured to drive the motor; and the current value is a coil current value of a coil current flowing through a coil of the motor.

6 . The drive circuit according to claim 5 , comprising the limit signal generating portion, the control portion, and a drive signal outputting portion connected to the motor; wherein
when the limit signal is inputted from the limit signal generating portion, the drive signal outputting portion lowers the duty ratio of the internal PWM signal inputted from the control portion to generate an output PWM signal, and outputs the output PWM signal to the motor driving portion.

7 . The drive circuit according to claim 5 , wherein
the control portion comprises a command value setting portion; and the command value setting portion sets the duty ratio corresponding to a command value based on a command signal.

8 . The drive circuit according to claim 7 , wherein
the control portion comprises an overload detecting portion; and the overload detecting portion detects that an overcurrent flows through the coil of the motor based on the limit signal.

9 . The drive circuit according to claim 8 , wherein
the control portion comprises a timer configured to start operation in response to an operation instruction and stop the operation after the predetermined time period elapses; and the control portion judges whether the predetermined time period elapses or not by the timer.

10 . The drive circuit according to claim 9 , wherein
when the duty ratio with the first predetermined value is set by the command value setting portion, and the limit signal is detected by the overload detecting portion, and the control portion judges that an overcurrent flows through the coil of the motor, the control portion sets the duty ratio to the second predetermined value during the predetermined time period by the timer.

11 . The drive circuit according to claim 1 , wherein the first predetermined value is 100%.

12 . The drive circuit according to claim 5 , comprising a limit signal converting portion connected to the limit signal generating portion; wherein
the limit signal converting portion comprises a charge and discharge circuit and generates a conversion signal obtained by converting the limit signal inputted from the limit signal generating portion.

13 . The drive circuit according to claim 12 , wherein
the control portion comprises a subtraction circuit connected to the limit signal converting portion; and the subtraction circuit generates a subtraction signal based on a command signal and the conversion signal.

14 . The drive circuit according to claim 13 , wherein
the control portion comprises a comparator connected to the subtraction circuit; and the comparator generates the internal PWM signal based on the subtraction signal inputted from the subtraction circuit and a triangular wave signal.

15 . A semiconductor apparatus comprising a control portion configured to, when a duty ratio is set to a first predetermined value, and a load apparatus is in an overload state, set the duty ratio to a second predetermined value smaller than the first predetermined value during a predetermined time period.

Assignees

• Toshiba Kk

Inventors

• Wang Shen

Classifications

• H02P6/14

  Electronic commutators · CPC title

• H02P29/40 Primary

  Regulating or controlling the amount of current drawn or delivered by the motor for controlling the mechanical load · CPC title

• H02P27/08

  with pulse width modulation · CPC title

• H02P6/08

  Arrangements for controlling the speed or torque of a single motor (H02P6/10, H02P6/28 take precedence) · CPC title

• H02P29/027

  the fault being an over-current · CPC title