L6235 View Datasheet(PDF) - STMicroelectronics

Part Name

Description

Manufacturer

L6235

DMOS DRIVER FOR THREE-PHASE BRUSHLESS DC MOTOR

STMicroelectronics 

L6235

Figure 10 shows the lower limit for the On Time tON for having a good PWM current regulation capacity. It has

to be said that tON is always bigger than tON(MIN) because the device imposes this condition, but it can be smaller

than tRCRISE - tDT. In this last case the device continues to work but the Off Time tOFF is not more constant.

So, small COFF value gives more flexibility for the applications (allows smaller On Time and, therefore, higher

switching frequency), but, the smaller is the value for COFF, the more influential will be the noises on the circuit

performance.

Figure 9. tOFF versus COFF and ROFF.

1.104

1.103

100

Roff = 100kΩ

Roff = 47kΩ

Roff = 20kΩ

10

1

0.1

1

10

100

Coff [nF]

Figure 10. Area where tON can vary maintaining the PWM regulation.

100

10

1.5µs (typ. value)

1

0.1

1

10

100

Coff [nF]

11/25

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