TPD4112K

2005-11-04

11

by making Duty of PWM less than 100%, or turning a motor from the outside compulsorily, and

creating edge to a hall sensor output. In order to enable the reboot after a lock as a system, it is

necessary to restrict and obtain on motor specification so that the maximum of Duty may become less

than 100%.

Description of Protection Function

(1)

Over current protection

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

V typ.) reaches 0.5 V higher than the shutdown voltage, the IC is automatically restored and the

IGBT is turned on again by the input.

turned on again by the input signal.

(3)

Thermal shutdown

The IC incorporates the thermal shutdown circuit to protect itself against the abnormal state when

its temperature rises excessively.

When the temperature of this chip rises due to external causes or internal heat generation and the

internal setting TSD, all IGBT outputs shut down regardless of the input. This protection function

has hysteresis (

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

automatically restored and the IGBT is turned on 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 differences in distance from the detection location in the IGBT (the source of

the heat) cause differences in the time taken for shutdown to occur. Therefore, the temperature of the

chip may rise higher than the thermal shutdown temperature when the circuit started to operate.

Duty ON

Over current setting value

PWM reference voltage

Duty OFF

Mask period

Over current shutdown

Retry

Triangle wave

Output current