SA56202 查看數據表（PDF） - Philips Electronics

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SA56202

One-chip motor driver

Philips Electronics 

Philips Semiconductors

SA56202

One-chip motor driver

where NPP indicates the number of pole pairs of the motor. FG has an open-drain output

for easy interfacing to 3 V and 5 V logic.

7.7 Sled motor driver

Two current-steering PWM channels are available to drive a stepper motor. Per channel

an external sense resistor Rsense is used that is connected to ground. A peak-current

control loop is implemented that modulates the duty cycle of the PWM signal. See

Figure 9.

Rext VINSLD 47 kΩ

47 kΩ

VVINREF

input amplifier

+Σ

−

R

Q

S

LOGIC

DRIVE

DRIVER

M

VVINREF

CLOCK

70 kHz

A

IO

Rsense

001aaa435

Fig 9. Peak-current control architecture of stepper motor driver.

The clock generator has a nominal frequency of fosc/256 = 70 kHz. See Figure 10 for the

transfer function from input voltage VVINSLD to output current at a typical Rsense of 0.5 Ω.

Input-to-output transconductance gain can be scaled down by connecting an external

resistor Rext in series with the input VINSLD.

IOUT (A)

1A

VVINSLD − VVINREF (V)

dead zone

−30 mV

+1 A/V

30 mV

−1 A

+1 A/V

001aaa436

Fig 10. Transfer function of stepper motor driver.

Both limit current and transconductance gain are related to Rsense in the following way:

Transconductance gain, V--I---oi-n- = 2-----×-----R-1---s--e--n---s--e

9397 750 12772

Preliminary data sheet

Limit current, ILIM = -2----×----1-R--V--s--e--n---s--e

Rev. 01 — 19 July 2004

© Koninklijke Philips Electronics N.V. 2004. All rights reserved.

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