L6208Q STMicroelectronics, L6208Q Datasheet - Page 10

• Manufacturer Part Number: L6208Q
• Description: Dmos Driver For Bipolar Stepper Motor
• Manufacturer: STMicroelectronics

Circuit description
4
4.1
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Circuit description
Power stages and charge pump
The L6208Q integrates two independent power MOS full bridges, each power MOS has an
R
conduction protection is implemented by using a dead time (t
internal timing circuit between the turn off and turn on of two power MOSFETs in one leg of
a bridge.
Pins VS
Using N-channel power MOS for the upper transistors in the bridge requires a gate drive
voltage above the power supply voltage. The bootstrapped supply (V
through an internal oscillator and few external components to realize a charge pump circuit
as shown in
with 10 V amplitude. Recommended values/part numbers for the charge pump circuit are
shown in
Table 5.
Figure 8.
DS(ON)
A
= 0.3 Ω (typical value @ 25 °C) with intrinsic fast freewheeling diode. Cross
Table
and VS
Figure
Charge pump external component values
Charge pump circuit
Component
5.
C
B
BOOT
C
R
D1
D2
must be connected together to the supply voltage (V
8. The oscillator output (pin VCP) is a square wave at 600 kHz (typically)
P
P
Doc ID 018710 Rev 1
VCP
D1
R
C
P
P
D2
VBOOT
C
BOOT
VS
A
VS
B
V
S
DT
1N4148
1N4148
220 nF
100
Value
10 nF
= 1 µs typical value) set by
Ω
BOOT
S
).
) is obtained
L6208Q
AM02559v1