L6205PD datasheet(8/21 Pages) STMICROELECTRONICS

8 / 21 page

L6205

8/21

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 = 1

µs 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

Figure 3. Charge Pump Circuit

LOGIC INPUTS

Pins IN1A, IN2A, IN1B and IN2B 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 ENA and ENB 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 ENA and ENB 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 REN and a ca-

pacitor CEN are connected as shown in Fig. 5. If the

driver is a standard Push-Pull structure the resistor

REN and the capacitor CEN are connected as shown

in Fig. 6. The resistor REN should be chosen in the

range from 2.2k

Ω to 180KΩ. Recommended values

for REN and CEN 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

Figure 5. ENA and ENB Pins Open Collector

Driving

Figure 6. ENA and ENB Pins Push-Pull Driving

TRUTH TABLE

= Don't care

High Z = High Impedance Output

CBOOT

220nF

10nF

100

Ω

1N4148

CBOOT

VSA

VCP

VBOOT

VSB

D01IN1328

INPUTS

OUTPUTS

IN1

IN2

OUT1

OUT2

High Z

GND

HLH

GND

HHH

D01IN1329

ESD

PROTECTION

OPEN

COLLECTOR

OUTPUT

REN

CEN

ENA or ENB

D02IN1349

PUSH-PULL

OUTPUT

REN

CEN

ENA or ENB

D02IN1350

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