Book Analog Interfacing to Embedded Microprocessors
L6201 from SGS-Thompson is a typical part. The L6201 can drive motors up
to 5A with supply voltages up to 48v. The L6201 includes internal flyback pro-
tection diodes and includes a thermal shutdown that turns the motors off if
the part overheats. The L6201 is available in DIP, SMT, and multiwatt pack-
ages (Figure 7.15).
The LM18200 from National is another motor driver IC. This part includes
a pin that provides a thermal warning when the device is about to overheat.
Unlike the L6201, the LMD18200 does not require a sense resistor in the
ground connection of the driver transistors. Instead, the LMD18200 has a sep-
arate pin that mirrors the current in the H-bridge. This pin (CURRENT
SENSE OUTPUT in Figure 7.15) typically carries 377 mA per amp of current
in the bridge. If a motor winding draws 2 amps, and a 4.99K resistor is con-
nected from the current sense pin to ground, then the voltage developed
across the resistor will be:
377 ¥ 10-6 ¥ 2 ¥ 4990 = 3
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