LB11851M Datasheet, PDF (4/6 Pages) Sanyo Semicon Device – Monolithic Digital IC Microprocessor Fan Motor Interface Driver

LB11851M
1. Power supply (VCC and VM) and ground
The wiring is separated into the control IC side (VCC line) and the motor output side (VM line) by the diode DI, which
protects the IC from destruction on reverse connection. The application circuit uses 1µF capacitors to prevent line
oscillation when kickback occurs. Similarly, 1µF capacitors are also used on the VCC line for power supply line
stabilization.
2. PWMIN
The LB11851M accepts an open-drain output signal from the microcontroller with this pin and controls the on/off
states of the PMOS transistor (OUT1P and OUT2P) outputs accordingly. A constant-current bias is provided from
5VREG internally to the IC.
3. FGIN
The LB11851M accepts a CMOS output from the microcontroller with this pin and determines the drive phase output
(OUT1P, OUT2P, OUT1N, or OUT2N).
4. 5VREG
This is the power supply for the microcontroller, Hall effect sensors, and other circuits. A capacitor with a value of
1µF is used for output stabilization. This pin has an output current capacity of 20mA.
5. SENSE
A sensing resistor is used for current detection. If the SENSE pin voltage exceeds 0.2V, the PMOS transistors are
turned off and only low side regeneration is performed.
Block Diagram
VCC
5VREG
PWMIN
5VREG
5VREG
5VREG
FGIN
Controller
100Ω
20kΩ
100Ω
20kΩ
20kΩ
OUT1N
300Ω
OUT1P
20kΩ
300Ω
OUT2N
OUT2P
SENSE
GND
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