E-L6205PD Datasheet, PDF (8/21 Pages) STMicroelectronics – DMOS DUAL FULL BRIDGE DRIVER

L6205
CIRCUIT DESCRIPTION
POWER STAGES and CHARGE PUMP
The L6205 integrates two independent Power MOS
Full Bridges. Each Power MOS has an Rd-
son=0.3ohm (typical value @ 25°C), with intrinsic
fast freewheeling diode. Cross conduction protection
is achieved using a dead time (td = 1µs typical) be-
tween the switch off and switch on of two Power MOS
in one leg of a bridge.
Using N Channel Power MOS for the upper transis-
tors in the bridge requires a gate drive voltage above
the power supply voltage. The Bootstrapped (Vboot)
supply is obtained through an internal Oscillator and
few external components to realize a charge pump
circuit as shown in Figure 3. The oscillator output
(VCP) is a square wave at 600kHz (typical) with 10V
amplitude. Recommended values/part numbers for
the charge pump circuit are shown in Table1.
Table 1. Charge Pump External Components
Values
C_BOOT
C_P
R_P
D1
220nF
10nF
100Ω
1N4148
D2
1N4148
Figure 3. Charge Pump Circuit
V_S
D1
D2
C_BOOT
R_P
C_P
VCP
VBOOT
VS_A VS_B D01IN1328
LOGIC INPUTS
Pins IN1_A, IN2_A, IN1_B and IN2_B are TTL/CMOS and
µC compatible logic inputs. The internal structure is
shown in Fig. 4. Typical value for turn-on and turn-off
thresholds are respectively Vthon=1.8V and
Vthoff=1.3V.
Pins EN_A and EN_B have identical input structure with
the exception that the drains of the Overcurrent and
thermal protection MOSFETs (one for the Bridge A
and one for the Bridge B) are also connected to these
pins. Due to these connections some care needs to
be taken in driving these pins. The EN_A and EN_B in-
puts may be driven in one of two configurations as
shown in figures 5 or 6. If driven by an open drain
(collector) structure, a pull-up resistor R_EN and a ca-
pacitor C_EN are connected as shown in Fig. 5. If the
driver is a standard Push-Pull structure the resistor
R_EN and the capacitor C_EN are connected as shown
in Fig. 6. The resistor R_EN should be chosen in the
range from 2.2kΩ to 180KΩ. Recommended values
for R_EN and C_EN are respectively 100KΩ and 5.6nF.
More information on selecting the values is found in
the Overcurrent Protection section.
Figure 4. Logic Inputs Internal Structure
5V
ESD
PROTECTION
D01IN1329
Figure 5. EN_A and EN_B Pins Open Collector
Driving
5V
5V
R_EN
OPEN
COLLECTOR
OUTPUT
EN_A or EN_B
C_EN
D02IN1349
Figure 6. EN_A and EN_B Pins Push-Pull Driving
5V
PUSH-PULL
OUTPUT
R_{EN ENA or ENB}
C_EN
D02IN1350
TRUTH TABLE
INPUTS
EN
IN1
IN2
L
X
X
H
L
L
H
H
L
H
L
H
H
H
H
OUTPUTS
OUT1 OUT2
High Z High Z
GND
GND
Vs
GND
GND
Vs
Vs
Vs
X = Don't care
High Z = High Impedance Output
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