TDA9112 datasheet(39/51 Pages) STMICROELECTRONICS

39 / 51 page

TDA9112

39/51

Figure 15. DC/DC converter controller block diagram

9.8 - MISCELLANEOUS

9.8.1 - Safety functions

The safety functions comprise supply voltage

monitoring with appropriate actions, soft start and

soft stop features on H-drive and B-drive signals

on HOut and BOut outputs and X-ray protection.

For supply voltage supervision, refer to paragraph

Power supply and voltage references on page 27

and Figure 1. A schematic diagram putting togeth-

er all safety functions and composite PLL1 lock

and V-blanking indication is in Figure 16.

9.8.2 - Soft start and soft stop functions

For soft start and soft stop features for H-drive and

B-drive signal, refer to paragraph Soft-start and

soft-stop

H-drive

page 31

and

subchapter DC/DC CONTROLLER SECTION on

page 37, respectively. See also the Figure 10. Re-

gardless why the H-drive or B-drive signal are

switched on or off (I2C bus command, power up or

down, X-ray protection), the signals always phase-

in and phase-out in the way drawn in the figure,

the first to phase-in and last to phase-out being the

H-drive signal, which is to better protect the power

stages at abrupt changes like switch-on and off.

The timing of phase-in and phase-out only de-

pends on the capacitance connected to HPosF pin

which is virtually unlimited for this function. Yet it

has a dual function (see paragraph PLL1 on

page 28), so a compromise thereof is to be found.

9.8.3 - X-ray protection

The X-ray protection is activated if the voltage lev-

el on XRay input exceeds VThrXRay threshold. As a

consequence, the H-drive and B-drive signals on

HOut and BOut outputs are inhibited (switched off)

after a 2-horizontal deflection line delay provided

to avoid erratic excessive X-ray condition detec-

tion at short parasitic spikes. The XRayAlarm I

bus flag is set to 1 to inform the MCU.

This protection is latched; it may be reset either by

VCC drop or by I

2C bus bit XRayReset(see chapter

I2C BUS CONTROL REGISTER MAP).

HDyCor

BRegIn

BComp

BIsense

BOut

N type

Soft start

H-drive edge

HDyCor sawtooth

H-flyback

~500ns

Monostable

HBOutEn

P type

VCC

Feedback

sawtooth

VThrBIsConf

BOutPol

(I2C)

XRayAlarm

(I2C)

BOutPh

(I2C)

discharge

HPosF

VThrBIsCurr

int.

ext.

int.

ext.

int.

ext. External sawtooth configuration

Internal sawtooth configuration

(+delay)

BOHEdge

(I2C)

VBReg

VC2

VC1

TDA9112 数据表(PDF) 39 Page - STMicroelectronics

TDA9112 数据表(HTML) 39 Page - STMicroelectronics

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51

数据表下载

链接网址

TDA9112 数据表(PDF) 39 Page - STMicroelectronics

TDA9112 数据表(HTML) 39 Page - STMicroelectronics

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51

数据表 下载

链接网址

数据表下载