AL3065A datasheet(13/16 Pages) DIODES

13 / 16 page

AL3065A

Application Information (continued)

This Device has a High Level of Integrated Built-In Protections:

1) Abnormal Condition

The AL3065A features shutdown at any abnormal condition protection circuit. For example, when the OVP pin voltage exceeds 3.2V, the IC is

latched off. Toggle EN pin to restart the IC. This feature can be used to shut down the IC under any defined abnormal condition.

2) Overvoltage Protection

The AL3065A integrates an OVP circuit. The OVP pin is connected to the center tap of voltage-divider (ROV1 and ROV2) connected between high-

voltage output and GND.

If the voltage at OVP pin exceeds 2.0V, which may result from open loop or excessive output voltage, all of the functions of the AL3065A are

disabled with output voltage falling. The OVP hysteresis is 200mV.

3) Overcurrent Protection

The AL3065A integrates an OCP circuit. The CS pin is connected to the voltage-sensor resistor (RCS) placed between the source of the MOSFET

and GND. If the voltage at CS pin exceeds 0.54V, the MOSFET is turned off immediately and does not turn on until the next cycle begins.

4) LED Short /Open Circuit Protection

When any LED string is short, the voltage at any of the CH1 to CH4 pins exceeds a threshold of approximately 7.3V during normal operation, and

the corresponding channel is latched off. Toggle VIN or EN to reset the latch. LED short detecting logic priority is lower than open LED and OVP

logic. The LED short detecting is triggered when 0.1V < VLED_MIN under dimming on mode, and disabled when LED open occurs until output

voltage resumes to the regulated voltage.

When any LED string is open, VOUT boosts up until the voltage at OVP pin reaches an approximate threshold of 2.0V. The IC automatically

ignores the open string, which has a corresponding pin voltage of less than 100mV, and the remaining string continues operation. If all strings are

open, and the voltage at OVP pin reaches a threshold of 2.0V, the MOSFET drive gate turns off, and the IC shuts down and latches.

5) VOUT Short and Open/Short Schottky Diode Protection

The AL3065A monitors the OVP pin, if the OVP pin voltage is less than 0.1V, MOSFET drive output will turn off. This protects the converter if the

output Schottky diode is open or VOUT is shorted to ground.

The AL3065A features Schottky diode/inductor short-circuit protection circuit. When the CS pin voltage exceeds 0.8V for more than 16 switching

clocks, the IC is latched off. Toggle EN pin to restart the IC. The voltage of CS pin is monitored after a short delay of tLEB.

6) VIN Undervoltage Lockout Protection

The AL3065A provides an undervoltage lockout circuit to prevent the device from undefined status when it starts up. The UVLO circuit shuts down

the device when VIN drops below 3.8V. The UVLO circuit has 200mV hysteresis, which means the device starts up again when VIN rises to 4.0V.

7) Overtemperature Protection

The AL3065A features overtemperature protection. If the junction temperature exceeds approximately +160°C, the IC shuts down until the junction

temperature is less than approximately +140°C. When the IC is released from over temperature shutdown, it starts a soft-start process.

AL3065A

Document number: DS41124 Rev. 1 - 2

13 of 16

www.diodes.com

August 2018

AL3065A bảng dữ liệu(PDF) 13 Page - Diodes Incorporated