BD2202G 查看數據表（PDF） - ROHM Semiconductor
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BD2202G Datasheet PDF : 26 Pages
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BD2202G BD2206G
Typical Application Circuit
Datasheet
VIN
VIN
CCIiNn
Current
limit
Charge
pump
UVLO
Control logic
EN
OFF ON
Therm al
s hutdown
GND
VOOUUTT
Cout
Rout
Application Information
Power supply noise may affect IC operation. To avoid this, connect a 1μF bypass capacitor or higher across IN and
GND.
Due to the internal body diode in the switch a CIN greater than COUT is highly recommended.
This application circuit does not guarantee its operation.
When using the circuit with changes to the external circuit constants, make sure to leave an adequate margin for
external components including AC/DC characteristics as well as dispersion of the IC.
Operation Description
BD2202G and BD2206G are high side switch ICs with over-current protection. The over-current protection is triggered
when the over-current condition exceeds the allowable period of time. Then the switch will be latched off until EN is
reset (toggled from high to low to high).
1. Switch ON/OFF Control
IN and OUT are connected to the drain and the source of the MOSFET switch respectively. IN is also used as a
power source input to the internal control circuit.
When the switch is turned on from the EN control input, a 150mΩ switch connects IN and OUT. During normal
condition, the switch is bidirectional. Therefore, when the voltage of OUT is higher than IN, current flows from OUT
to IN.
There is a parasitic diode (body diode) between drain and source of the MOSFET switch. So, even when the switch
is off, when the voltage of OUT is higher than IN, the current flows through the body diode from OUT to IN.
2. Over-Current Detection (OCD)
The over-current detection circuit limits current flowing in the MOSFET switch 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).
(1) When the switch is turned on while the output is in short-circuit status, the switch goes into current limit
status immediately.
(2) 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.
(3) 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 shutdown. The OFF switch is set to latch off mode. The latch is reset when EN terminal is
toggled or when UVLO is detected.
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21.Aug.2014 Rev.003
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