BD91361MUV_14 Datasheet, PDF (12/27 Pages) Rohm – Synchronous Buck Converter with Integrated FET

BD91361MUV
Datasheet
4. Setting the Output Voltage
Output voltage shifts step by step, depending on the bit setting, to control the overshoot/undershoot that happens when
changing the setting of output voltage. A delay of 8 steps (Max) will occur from the bit switching until output voltage
reaches the setting value.
VID<2:0>
(0,1)
(1,1)
0.96V
V_OUT
0.72V
tVID (Max)=0.04ms
(a) Switching 2 bits synchronously
(c) Switching the bit during counting
VID<1>
VID<0>
Count STOP
VOUT
5µs(Max)
About 10µs from bit switching
(b) Switching 2 bits with the time lag
VID<1>
VID<0>
<1>
<0>
Count STOP
VOUT
About 10µs from bit switching
Count STOP
VOUT
About 10µs from switching the last bit
Figure 29. Timing Diagram of Setting the Output Voltage
It is possible to set the output voltage by setting VID<0> to <1> 0 or 1, as shown in the table below.
By default, VID<1:0> terminal is set to (0,0) by the high impedance pull down resistor inside the IC.
By pulling up/down the resistor for about 10kΩ, the default value can be changed.
Diagram 1. Table of Output Voltage Setting
VID<1>
VID<0>
VOUT
0
0
VOUT
0
1
0.9 X VOUT
1
0
1.1 X VOUT
1
1
1.2 X VOUT
(Note )
After 10µs(Max) from the bit change, VOUT starts to change.
Required time for one step (10% shift of VOUT) of VOUT is 10µs(Max).
From bit switching until the output voltage reaches the setting value, a delay of tVID (Max)=0.04ms will occur.
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