TPD4131K

2010-11-18

11

either the edge of a Hall sensor output or the edge of an internal PWM signal, but neither edge is

available due to the motor lock and duty 100 % command. In order to reboot after a lock, the high-side

power voltage must return to a level 0.5 V (typ.) higher than the voltage decrease protection level, and

a high-side input signal must be introduced. As a high-side input signal is created by the

aforementioned level shift pulse, it is possible to reboot by reducing PWM duty to less than 100 % or

by forcing the motor to turn externally and creating an edge at a Hall sensor output. In order to

ensure reboot after a system lock, the motor specification must be such that maximum duty is less

than 100 %.

Description of Protection Function

(1)

Over-current protection

The IC incorporates an over-current protection circuit to protect itself against over current at startup

or when a motor is locked. This protection function detects voltage generated in the current-detection

output, which is on, temporarily shuts down after a mask period, preventing any additional current

from flowing to the IC. The next PWM ON signal releases the shutdown state.

(2)

Under-voltage protection

The IC incorporates under-voltage protection circuits to prevent the IGBT from operating in

automatically restored and the IGBT is turned on/off again by the input.

typ.)), the IGBT is turned on/off again by the input signal.

(3)

Thermal shutdown

The IC incorporates a thermal shutdown circuit to protect itself against excessive rise in temperature.

When the temperature of this chip rises to the internal setting TSD due to external causes or internal

heat generation, all IGBT outputs shut down regardless of the input. This protection function has

hysteresis

ΔTSD (= 50 °C typ.). When the chip temperature falls to TSD − ΔTSD, the chip is

automatically restored and the IGBT is turned on/off again by the input.

Because the chip contains just one temperature-detection location, when the chip heats up due to the

IGBT for example, the distance between the detection location and the IGBT (the source of the heat)

can cause differences in the time taken for shutdown to occur. Therefore, the temperature of the chip

may rise higher than the initial thermal shutdown temperature.

Duty ON

Over-current setting value

PWM reference voltage

Duty OFF

Mask period

Over-current shutdown

Retry

Triangle wave

Output current