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L6235

Circuit description

35

5

Circuit description

5.1

Power stages and charge pump

The L6235 device integrates a 3-phase bridge, which consists of 6 Power MOSFETs

connected as shown in Figure 1: Block diagram on page 3. Each power MOS has an

patterns are generated by the PWM current controller and the hall effect sensor decoding

logic (see Section 6: PWM current control on page 13 and Section 8: Decoding logic on

typical value) set by internal timing circuit between the turn off and turn on of two Power

MOSFETs in one leg of a bridge.

Using N-channel power MOS for the upper transistors in the bridge requires a gate drive

through an internal oscillator and few external components to realize a charge pump circuit

as shown in Figure 5. The oscillator output (pin VCP) is a square wave at 600 KHz

(typically) with 10 V amplitude. Recommended values/part numbers for the charge pump

circuit are shown in Table 6.

Figure 5. Charge pump circuit

Table 6. Charge pump external component values

Component

Value

22 0nF

10 nF

100



1N4148

1N4148

D2

D1

VCP

VBOOT

D01IN1328