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BD2202G BD2206G
Datasheet
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TSZ22111･15･001
TSZ02201-0E3E0H300180-1-2
11.Mar.2013 Rev.001
●Operation Description
BD2202G and BD2206G are high side switch ICs with over-current protection function. The operating voltage range is
from 2.7V to 3.6V and the current limit value is set to 400mA and 1A respectively.
When an over-current condition lasts longer than its over-current shutdown time, the switch turns OFF. The OFF switch
is set to latch mode. The switch set to latch mode returns to normal by toggling EN pin from High to Low to High.
1.Switch On/Off control
VIN terminal and VOUT terminal are connected to the drain and the source of switch MOSFET respectively. And the
VIN terminal is used also as power source input to internal control circuit.
When the switch is turned on from EN control input, VIN and VOUT are connected by a 150mΩ switch. In normal
condition, the switch is bidirectional. Therefore, when the voltage of VOUT is higher than VIN the current flows from
VOUT to VIN.
In the switch MOSFET, there is a parasitic diode (body diode) between drain and source. So, even when the switch is
off, when voltage of VOUT is higher than VIN, the current flows through the body diode from VOUT to VIN.
2. Over current detection (OCD)
The over current detection circuit limits current flowing in switch MOSFET when it exceeds its limit threshold. There
are three types of responses against over current. The over current detection circuit is in operation when the power
switch is ON (when EN signal is active).
2-1 When the switch is turned on while the output is in short-circuit status
When the switch is turned on while the output is in short-circuit status, the switch goes into current limit status
immediately.
2-2 When the output short-circuits while the switch is on
When the output short-circuits or high-current load is connected while the switch is on, very large current flows
until the over current limit circuit reacts. When the current detection and limit circuit works, current limitation is
carried out.
2-3 When the output current increases gradually
When the output current increases gradually, current limitation does not work until the output current exceeds the
over current detection value. When it exceeds the detection value, current limitation is carried out.
3.Over current shutdown
When the over current detection circuit detects an over current, TBLANK timer starts working. When the over current
condition disappears before TBLANK2 stage, TBLANK timer is reset. When the over current condition progresses to
more than TBLANK1, the switch is shut off. The OFF switch is set to latch off mode. The latch is reset when EN
terminal is toggled or when UVLO is detected.
4.Under voltage lockout (UVLO)
UVLO keeps the power switch off until VIN voltage exceeds 2.3V (Typ.). Moreover, from a power switch ON situation,
if VIN voltage drops to 2.2V (Typ.), the power switch is set to OFF. UVLO has a 100mV hysteresis. The under voltage
lock out circuit is in operation when power switch is ON (when EN signal is active).
5.Thermal shutdown
When the chip temperature increases to 160°C (Typ.), the thermal shut down circuit works and the power switch is
turned OFF. When the chip temperature falls to 140°C (Typ.), the power switch output returns to normal. This
operation will repeat itself until the causes of the chip temperature rise are removed or until the power switch output is
turned off.
The thermal shutdown circuit is in operation when the power switch is ON (when EN signal is active).
