BD81A04AMUV-M Datasheet, PDF (13/37 Pages) Rohm – 4ch White LED Driver with Buck-Boost and Built-in FET (32 LED Maximum)

BD81A04AMUV-M BD81A04AEFV-M
Timing Chart
Datasheet
Figure 18. Protection Sequence Timing Chart
Note 1ç Turn on EN after V_CC reaches the operating voltage range.
Note 2ç The order of turning on PWM and SYNC is arbitrary.
Note 3ç Approximately 100ms of delay when fosc=300kHz.
Note 4 The TSS expresses the time from UVLO release/cancel until the start of DC/DC switching. (Details on page 19)
Note 5ç The timing chart is defined when pulling –up the FAIL Pin towards the VREG.
1. In between V_OVP<1.0V, regardless it is PWM input, the DC/DC switching operation will be carried out (Pre-Voltage).
By the V_OVP≧1.0V, the pre-voltage ends.
2. The LED2 is Open mode.
VLED2ʻ0.3V and V_OVPʼ1.8V are detected and LED2 is Turned OFF. →FAIL2 becomes Low
3. LED3 is Short mode
VLED3ʼ4.5V is detected and after 100ms, the (@fosc=300kHz) LED3 will Turn OFF.
4. VLED4 is shorted to GND.
(1) Output Voltage High, and OVP is detected with V_OVPʼ2.0V.
→SS discharged and FAIL1 becomes low.
(2) After detection of VLED4ʻ0.3V, shutdown after about 100ms (@fosc=300kHz).
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