AS3658F-BCTP datasheet(135/158 Pages) AMSCO

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AS3658

Data Sheet Confidential - Deta il ed Descri ption - System Functi ons

10.5

Protection Functions

All LDO’s, the DCDC step ups and DCDC step downs have an integrated overcurrent protection. An overtemperature

protection of the chip is also integrated which can be switched on with the serial interface signal temp_pmc_on

(enabled by default; it is not recommended to disable the overtemperture protection). The chip has two signals for the

serial interface: ov_temp_110 and ov_temp_140. The flag ov_temp_110 is automatically reset if the overtemperature

condition is removed, whereas ov_temp_140 has to be reset by the serial interface with the signal rst_ov_temp_140.

If the flag ov_temp_140 is set, an automatic reset of the complete chip is initiated. The flag ov_temp_140 is not

affected by this reset cycle allowing the software to detect the reason for this unexpected shutdown.

Table 154. Overtemperature Detection

Symbol

Parameter

Min

Typ

Max

Unit

Note

Table 155. Overtermperature detection Bit definition

Addr:106

Overtemperature Control

These bits control the startup and are set by factory test

Bit

Bit Name

Default

Access

Description

10.5.1 Temperature Supervision

A temperature sensor is implemented to provide over-temperature protection of the chip. It generates two flags linked

to the two temperature thresholds (110 degrees, 140 degrees). Both thresholds have an hysteresis to prevent

oscillation effects.

First threshold (110 degrees) sets the flag ov_temp_110, signalling the serial interface part and software the 110

degrees overtemperature condition. If enabled (ovtmp_int_mask=0), an interrupt can be send (interrupt ‘ovtmp’). Thus

software can react and can shutdown power consuming functions to decrease temperature.

The second threshold (140 degrees) initiates a reset cycle and sets ov_temp_140: this sets all regulators into power-

down mode and stops charging, and performs the reset cycle of the AS3658.

rst_ov_temp_140 flag

In case of overtemperature and an activated reset (temp_pmc_on=1), the system loses any information about the error

which activated the reset state. Therefore, a flag is implemented, which indicates that the reset was caused by

overtemperature activation (ov_temp_140 is set). This flag is only resetable by writing ‘1’ to rst_ovtemp_140.

T110

ov_temp_110 rising

threshold

110

125

ºC

T140

ov_temp_140 rising

threshold

125

140

155

ºC

Thyst

ov_temp_110 and

ov_temp_140

hysteresis

5ºC

temp_pmc_on

R/W

Switch on / off of temperature supervision; default: on

– all other bits are only valid if set to ‘1’

Leave at 1, do not disable

ov_temp_110

Flag that the overtemperature threshold 1 (T110) has

been reached

ov_temp_140

Flag that the overtemperature threshold 2 (T140) has

been reached – this flag is not reset by a

overtemperature caused reset and has to be reset by

rst_ov_temp_140

If the overtemperature threshold 2 has been reached,

the flag ov_temp_140 is set and a reset cycle is

started. ov_temp_140 should be reset by writing 1 and

afterward 0 to rst_ov_temp_140

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