UH477_15 Datasheet, PDF (5/6 Pages) Unisonic Technologies – SINGLE PHASE DC MOTOR DRIVE IC

UH477
Preliminary
LINEAR INTEGRATED CIRCUIT
 APPLICATION CIRCUIT
The Example of Typical Application Circuit
A typical application circuit is shown as follows. The red, yellow, and black wires are the input points of the
motor system: Red--the input of power supply; Yellow--the output of FG; Black--the ground signal. R_C is an external
pull-up resistance for the use of measuring FG signal.
The value of R_C can be calculated by the transistor saturation voltage (V_ON), sink current (I_C), and off-level
voltage (V_C).
R_C

V_C
 V_ON
I_C
For example:
V_C=+5V for TTL level; I_C= 10mA at 0.2V saturation voltage; The safety value of R_C=470Ω
There is a reverse protection diode D1 in the circuit. As if the red and black wires reversely connect with the
power source, the current flows through the ground via IC and coils L1 and L2 to power supply. Under such kind of
circumstances the IC and coils are easy to be burned out. From that, this reverse protection diode is necessary in
the design. Meanwhile, an extra voltage drop on the supply voltage should be taken into consideration, which is
caused by the reverse protection diode.
The capacitor C1 is designed to reduce the ripple noise during the transient of the output stages, and its value
is determined by the coil impedance and characteristics.
R wire
+V_C
R_C
Y wire
B wire
D1
C1
V_CC
NO
L1
UH477
SO
GND
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