BD9745EKN Datasheet, PDF (16/22 Pages) Rohm – Silicon Monolithic Integrated Circuit

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11．Nch DRIVER
This CMOS inverting output circuit is a Driver block with built-in and external Nch FET. PVCC pin voltage for
DRIVER must have same voltage with VCC pin voltage for main block.
12．Pch DRIVER
This CMOS inverting output circuit is a Driver block with built-in and external Pch FET.
13．Road SW
This circuit controls high-side load switch with CH6, 7. HS6H, 7H (40,46pin) is input, and HS6L, 7L (41,45) is
output. This circuit controls by ramping the HS6L, 7L voltage on startup to decrease in-rush current.
14．Back gate Control
This circuit controls to switch back-gate voltage of Built-in Pch-FET. (CH1, 2,4) In monolithic IC of P-Sub, the
parasitic diode remains between back-gate (cathode), and source, drain (anode). This circuit cut current pass
through the parasitic diode in step-up situation on STB OFF.
15．ON/OFF LOGIC
The output of each channel can be turned on and off by the input voltage applied on the STB pin.
The channel is “ON” when the voltage of the STB pin is above 1.5 V.
The channel is “OFF” when the voltage applied at STB pin is 0 V or the pin is left open.
When all channels are “OFF”, the device is at Stand-by State.
Each logic pin is connected to GND via a 400kΩpull-down resistor.
16．UDSEL LOGIC
The output of CH1, 2, 4 can be switched step-down/up by input voltage applied on the UDSEL pin.
The output is at step-up mode when UDSEL is GND, and step-down mode when UDSEL is VBAT.
UDSEL pin must be connected to GND or VBAT to prevent unstable logic state, due to this logic is
CMOS inverter powered VBAT.
REV. D