Data Sheet

13

Rev. 1.0, 2008-12-04

TLE7184F

MOSFET Driver

5.3

Bootstrap Principle

The TLE7184F provides a bootstrap based supply for its high side output stages. The benefit of this principle is a

fast switching of the high side switches - supporting active freewheeling in high side.

The bootstrap capacitors are charged by switching on the external low side MOSFETs connecting the bootstrap

capacitor to GND. Under this condition the bootstrap capacitor will be charged from the VREG capacitor. If the low

side MOSFET is switched off and the high side MOSFET is switched on, the bootstrap capacitor will float together

with the SHx voltage to the supply voltage of the bridge. Under this condition the supply current of the high side

output stage will discharge the bootstrap capacitor. This current is specified. The size of the capacitor together

with this current will determine how long the high side MOSFET can be kept on without recharging the bootstrap

capacitor.

When all external MOSFETs are switched off, the SHx voltage can be undefined. Under this condition, the

bootstrap capacitors can be discharged, dependent on the SHx voltage.

5.4

Electrical Characteristics

Electrical Characteristics MOSFET Drivers

V

(unless otherwise specified)

Pos.

Parameter

Symbol

Limit Values

Unit

Conditions

Min.

Typ.

Max.

Inputs

5.4.1

Low level input voltage of ILx; IHx

V

I_LL

––1.6

V

–

5.4.2

High level input voltage of ILx; IHx

V

I_HL

2.8

––V

–

5.4.3

d

VI

100

––mV

–

5.4.4

IHx pull-up resistors to VDD

R

IH

33.5

–

66.5

k

Ω

–

5.4.5

ILx pull-down resistors to GND

R

IL

210

–

490

k

Ω

–

MOSFET driver output

5.4.6

Output source resistance

R

Sou

2–13.5

Ω

Iload=20mA

5.4.7

Output sink resistance

R

Sink

2–9

Ω

Iload=20mA

5.4.8

High level output voltage Gxx vs.

Sxx

V

Gxx1

–

11

14

V

13,5V

<=V

V

V

I

5.4.9

High level output voltage GHx vs.

SHx1)

V

Gxx2

6––V

V

C

dc=94%;

f

5.4.10

High level output voltage GHx vs.

SHx1)3)

V

Gxx3

6

+

V

diode

––V

V

C

dc=94%;

f

passive

freewheeling