Data Sheet AS8446

Revision 1.8, Date 2005-03-17

Page 31 of 35

Over Temperature Detection

On Chip Over Temperature Detection

The on chip temperature detection sets the signal PTover_in high if the chip temperature climbs above the specified level. This

over temperature detection has a hysteresis of about 20 °C.

PARAMETER

SYMBOL

MIN

TYP

MAX

UNIT

NOTE

Recovery Temperature

+130

+140

+150

°C

Information Parameter

Shutdown Temperature

+150

+160

+170

°C

Information Parameter

On chip temperature voltage

VTEMP

1

1.4

V

threshold voltage of the on chip

over temperature comparator

VOTI

0.8

1

V

Information Parameter

Hysteresis of the over temperature

comparator

VOTIHYST

30

50

mV

Information Parameter

External Over Temperature Detection

The over temperature detection is realized with an external temperature sensor (e.g. NTC). The threshold value of the voltage

PARAMETER

SYMBOL

MIN

TYP

MAX

UNIT

NOTE

Over Temperature threshold value

VDD/2 –

0.05

VDD/2 +

0.05

V

Negative Hysteresis

30

70

mV

The over temperature signal PTover_ex is defined in the following way:

Analog MUX and Analog Output Buffer

The following analog measurement channels and digital signals are output via an analog MUX and an analog buffer to the pin

ADC, the MUX is controlled by register R15<3:0>

Analog MUX function

PARAMETER

SYMBOL

TYP

NOTE

A_current

Normal motor current measurement

channel

R15 = 0

A_overc

Motor over current measurement

channel

R15 = 1

Vbat_mon

Battery voltage monitoring

R15 = 2

TP

Temperature sensor analog value

R15 = 3

Used in

normal

application

to control /

regulate the

system

Vtemp

Temperature voltage

R15 = 4

PVover

Over voltage signal

R15 = 5

PVunder

Under voltage signal

R15 = 6

PTover_ex

Over temperature signal, extern

R15 = 7

PTover_in

Over temperature signal, intern

R15 = 8

Used for test

purposes

only