L6208Q datasheet(12/34 Pages) STMICROELECTRONICS

12 / 34 page

Circuit description

L6208Q

12/34

DocID018710 Rev 3

Circuit description

5.1

Power stages and charge pump

The L6208Q device integrates two independent power MOSFET full bridges, each power

MOSFET has an RDS(ON) = 0.3  (typical value at 25 °C) with intrinsic fast freewheeling

diode. Cross conduction protection is implemented by using a deadtime (tDT = 1 µs typical

value) set by internal timing circuit between the turn-off and turn-on of two power MOSFETs

in one leg of a bridge.

Pins VSA and VSB must be connected together to the supply voltage (VS).

Using an N-channel power MOSFET for the upper transistors in the bridge requires a gate

drive voltage above the power supply voltage. The bootstrapped supply (VBOOT) is obtained

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

circuit, as shown in Figure 8. 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 5.

Figure 8. Charge pump circuit

Table 5. Charge pump external component values

Component

Value

CBOOT

220 nF

10 nF

100



1N4148

AM02559v1

CBOOT

VSA

VCP

VBOOT

VSB

L6208Q bảng dữ liệu(PDF) 12 Page - STMicroelectronics