TLE 4729 G

Data Sheet

24

V1.2, 2008-03-18

Application Hints

The TLE4729G is intended to drive both phases of a stepper motor. Special care has

been taken to provide high efficiency, robustness and to minimize external components.

Power Supply

The TLE4729G will work with supply voltages ranging from 5 V to 16 V at pin

exceeding 16 V at

guaranteed. As soon as the voltage drops below approximately 16 V the TLE4729G

works promptly again.

As the circuit operates with chopper regulation of the current, interference generation

problems can arise in some applications. Therefore the power supply should be

decoupled by a 0.1

µF ceramic capacitor located near the package. Unstabilized

supplies may even afford higher capacities.

Inhibit Mode

In the case of low at all four current program inputs IXX the device will switch into inhibit

condition; the current consumption is reduced to very low values.

When starting operation again, i.e. putting at least one IXX to high potential, the Error 1

output signals an open load error if the corresponding phase input is high. The error is

reset by first recirculation in chop mode.

Current Sensing

The current in the windings of the stepper motor is sensed by the voltage drop across

transistor as soon as the voltage drop reaches certain thresholds (typical 0 V, 0.07 V,

0.45 V and 0.7 V). These thresholds are not affected by variations of

instabilized supplies will not affect the performance of the regulation. For precise current

level it must be considered, that internal bounding wire (typ. 60 m

Due to chopper control fast current rises (up to 10 A/

µs) will occur at the sensing

resistors. To prevent malfunction of the current sensing mechanism

pure ohmic. The resistors should be wired to GND as directly as possible. Capacitive

loads such as long cables (with high wire to wire capacity) to the motor should be

avoided for the same reason.

Synchronizing Several Choppers

In some applications synchrone chopping of several stepper motor drivers may be

desirable to reduce acoustic interference. This can be done by forcing the oscillator of

the TLE4729G by a pulse generator overdriving the oscillator loading currents

(approximately

± 120 µA). In these applications low level should be between 0 V and

0.8 V while high level should between 3 V and 5 V.