BD8255MUV-M_16 Datasheet, PDF (30/45 Pages) Rohm – 6ch System Motor Driver For Car AV

BD8255MUV-M
Noise Suppression
The following are possible causes of noise of the PWM driver.
A. Noise from power line or ground
B. Radiated noise
- Countermeasures against A -
(1) Reduce impedance in wiring for the driver's 5 V power supply (SPRNF, SLRNF1, SLRNF2, PREVCC, AVM) and power
GND (SPGND, SLGND, ACTGND) lines where high current flows. Make sure that they be separated from power
supply lines of other devices at the root so that they do not have common impedance. (Figure 25.)
5V line No.1
GND
5V line No.2
Separate at the
root as much as
possible.
47μF
47μF
Other Devices
than Driver
0.1μF
0.1μF
Driver IC
(BD8255MUV-M)
Figure 25. Pattern Example
(2) Provide a low ESR electrolytic capacitor between the power terminal and the ground terminal of the driver to achieve
strong stabilization. Provide a ceramic capacitor with good high frequency property next to the IC.
Also provide a ceramic capacitor with good high frequency property between RNF and GND. (Figure 26.)
Then power supply ripple due to PWM switching and spindle motor rotation can be reduced.
SPVM
0.1μF
SPVM
0.1μF
R_SLRNF
0.1μF
SLRNF1,2
SLGND
(Pin17)
R_SPRNF
0.1μF
U_OUT
SPRNF
SPGND
(Pin16)
V_OUT W_OUT
SLGND
(Pin17)
SPGND
(Pin16)
SPVM:
Strongly stabilize with
electrolytic capacitor.
SPGND
(Pin16)
Power supply
5V
0.1μF
SPGND
(Pin16)
47μF or greater
R_SPRNF
0.1μF
SPGND
(Pin16)
12 ^SPRNF
BD8255MUV-M
(a) Send motor
(b)Spindle
(c) Around Spindle Power Supply
Figure 26. Position of Ceramic Capacitors
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