bd9763fvm ROHM Co. Ltd., bd9763fvm Datasheet - Page 7

• Manufacturer Part Number: bd9763fvm
• Description: Single-output Step-up, High-efficiency Switching Regulators Controller Type
• Manufacturer: ROHM Co. Ltd.

●Timing chart
(6) Setting the output voltage
(7) CTL/SS setting the soft start time
The time after CTL/SS is released before the output voltage starts to rise.
The output voltage is calculated by the following equation.
Vo = VINVth･(R1+R2)/R2 [V]
R1,R2 : Resistor divider network
VINth : Error amp threshold voltage (typ.1V)
t(start) = CCTL･(VDo-Voff)/Iss [S]
The time after the output voltage starts up before it reaches the specified output level.
t(soft) = CCTL･(VDUTY-VDo)/Iss [S]
VDUTY = VDo+0.5･(1-VIN/VOUT) [V]
(but Vo<VIN･5 because of MAXDUTY Min=80%)
CCTL : CTL/SS–GND capacitande Vdo : 0% duty threshold (Typ 1.6V) Voff : Output off CTL/SS voltage
Iss : CTL/SS charge current (Typ 1uA) VDUTY : stabilization operating ON duty.
Dead-time
voltage
Stand-by threshold
voltage
Output waveform
t(start)
ON/OFF
t(soft)
Oscillator output
approximated equation
approximated equation
CTL/SS terminal voltage
7/12
FB terminal voltage
VDUTY