STLD20D datasheet(10/31 Pages) STMICROELECTRONICS

10 / 31 page

Functional description

STLD20D

10/31

5.6

Over temperature protection (OTP)

An integrated temperature sensor senses the temperature of the junction of the controller.

As soon as this temperature exceeds 110°C min fixed internally, the controller is

automatically turned OFF. When the temperature is reduced of 5°C the operation of the

device automatically recovers.

5.7

Over voltage protection (OVP)

In case of failure and if the LED branch is cut, then there is no signal at the feedback pin FB

(

Figure 3.), the PWM controller will then switches with a maximum duty cycle. This will

generate a voltage at the pin SW and VOUT that can exceed the maximum rating of the

device.

The overvoltage protection block senses the output voltage at the pin VOUT (Figure 3.). If the

voltage exceeds 18.5VDC typical the controller is automatically turned OFF.

When the voltage is reduced of 0.7V, the operation of the device automatically recovers.

5.8

Efficiency

(

Figure 4. & Figure 9.)

The efficiency takes into account these following losses:

●

RLED ohmic losses

●

Boost switch SW losses

●

Load Disconnect Switch LDS

●

Boost inductor losses

●

Boost diode losses

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