BU91520KV-M Datasheet, PDF (36/45 Pages) Rohm – Low Duty LCD Segment Driver

BU91520KV-M
Voltage Detection Type Reset Circuit (VDET)
The Voltage Detection Type Reset Circuit generates an output signal that resets the system when power is applied for
the first time and when the power supply voltage drops (that is, for example, the power supply voltage is less than or equal to
the power down detection voltage (VDET = 1.8V typ.). To ensure that this reset function works properly, it is recommended that
a capacitor be connected to the power supply line so that both the power supply voltage (VDD) rise time when power is first
applied and the power supply voltage (VDD) fall time when the voltage drops are at least 1ms.
VDD
t1
t2
VDD min
VDD min
t3
VDD = 1.0V
Power supply voltage VDD fall time: t1 > 1ms
Power supply voltage VDD rise time: t2 > 1ms
Figure 31. VDET Detection Timing
Reset Condition
The internal status after power supply has been reset as the following table.
Instruction
Key Scan mode
S1/P1/G1 to S6/P6/G6 Pin
LCD Bias
LCD Duty
Inversion
DISPLAY Frequency
Display Clock mode
LCD Display
Power Mode
PWM/GPO Output
PWM Frequency
PWM Duty
At Reset Condition
[KM0,KM1,KM2]=[1,1,1]: Keyscan no use
[P0,P1,P2]=[0,0,0]:all segment output
DR=0:1/3-Bias
DT=0:1/4-Duty
FL=0:Line Inversion
[FC0,FC1,FC2]=[0,0,0]:fosc/12288
OC=0:Internal oscillator
SC=1:OFF
BU0 to 2=[1,1,1]:Power saving mode
PGx=0:PWM output(x=1 to 6)
[PF0,PF1,PF2,PF3]=[0,0,0,0]: fosc /4096
[Wn0 to Wn7]=[0,0,0,0,0,0,0,0]
1/256xTp(n=1 to 6,Tp=1/fp)
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TSZ02201-0P4P0D301340-1-2
22.Jan.2016 Rev.001