E-L6258EA View Datasheet(PDF) - STMicroelectronics

Part Name

Description

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E-L6258EA

PWM controlled high current DMOS universal motor driver

STMicroelectronics 

L6258EA

Functional description

With a positive differential voltage on VDAC (see Figure 5, the transconductance loop will be

positively unbalanced respected Vr.

In this case being the error amplifier output voltage greater than Vr, the output of the first

comparator is a square wave with a duty cycle higher than 50%, while the output of the

second comparator is a square wave with a duty cycle lower than 50%.

The variation in duty cycle obtained at the outputs of the two comparators is the same, but

one is positive and the other is negative with respect to the 50% level.

The two driving signals, generated in this case, drive the two outputs in such a way to have

switched current flowing from OUT_A through the motor winding to OUT_B.

With a negative differential voltage VDAC, the transconductance loop will be negatively

unbalanced respected Vr.

In this case the output of the first comparator is a square wave with a duty cycle lower than

50%, while the output of the second comparator is a square wave with a duty cycle higher

than 50%.

The variation in the duty cycle obtained at the outputs of the two comparators is always of

the same.

The two driving signals, generated in this case, drive the the two outputs in order to have the

switched current flowing from OUT_B through the motor winding to OUT_A.

2.7

Current control loop compensation

In order to have a flexible system able to drive motors with different electrical characteristics,

the non inverting input and the output of the error amplifier ( EA_OUT ) are available.

Connecting at these pins an external RC compensation network it is possible to adjust the

gain and the bandwidth of the current control loop.

15/32

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