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TSZ02201-0F2F0AJ00280-1-2

© 2020 ROHM Co., Ltd. All rights reserved.

11.Jun.2020 Rev.001

www.rohm.com

TSZ22111 • 15 • 001

BD9G500EFJ-LA

0V

Soft Start

hys

UVLO

OFF

Normal operation

Normal operation

UVLO

UVLO

ON

Reference Voltage

1.0 V(Typ)

100 ns(Typ)

400 ns(Typ)

OVDIS

(Over Volt age Discharge)

Discharge MOS

GATE

2.

Protective Functions - coutinued

2.2

Under Voltage Lockout Protection Function (UVLO)

This is under voltage lockout block. It shuts down the device when the VIN pin voltage falls to 6.4 V (Typ) or less.

The UVLO threshold voltage has a hysteresis of 200 mV (Typ).

2.3

Over Voltage Discharge Function (OVDIS)

When the FB pin voltage is 1.0 V (Typ) or more and 2.0 V (Typ) or less and remains in that state for 16 cycle, the

Discharge MOS On-time is set to 400 ns (Typ) and discharge output voltage.

Figure 35. OVDIS Timing Chart

2.4

Over Voltage Protection Function (OVP)

When the FB pin voltage is 1.2 V (Typ) or more, it turns High-Side MOSFET OFF. After FB pin voltage drops, it

returns to normal operation with hysteresis. This IC has Discharge MOS. This MOS turns on 100 ns (Typ) at each

duty cycle. When the FB pin voltage is 2.0 V (Typ) or more, it turns Discharge MOS off also.

2.5

Thermal Shutdown Function (TSD)

This is the thermal shutdown circuit that prevents heat damage to the IC. Normal operation should always be

within the IC’s power dissipation rating. However, if the rating is exceeded for a continued period and the junction

temperature (Tj) rises to 175 °C (Typ) or more, the TSD circuit will operate and turn OFF the output MOSFET.

When the Tj falls below the TSD threshold, the circuits are automatically restored to normal operation. Note that

the TSD circuit operates in a situation that exceeds the absolute maximum ratings and therefore, under no

circumstances, should the TSD circuit be used in a set design or for any purpose other than protecting the IC

from heat damage.

Figure 34. UVLO Timing Chart