L99VR02XP datasheet(28/50 Pages) STMICROELECTRONICS

28 / 50 page

4.7

Thermal warning and thermal shutdown

To warn the microcontroller about a severe temperature increase, two thermal warning outputs have been

implemented (one for each regulator). Through TC_CONF it is possible to set the management of a thermal

shutdown event.

Table 18. TC_CONF setup

Event

TC_CONF in DEFAULT conf. (TC_CONF = GND)

TC_CONF in OR conf. (TC_CONF

= VS_LDO1)

THERMAL

SHUTDOWN

LDO1 and LDO2 are fully independent of each other and

monitored by two different thermal clusters

In tracking mode: if LDO1 is in thermal shutdown and

TRK_MODE = GND (see the Table 19), LDO2 is untied by LDO1

and keeps the normal activity. In case of TRK_MODE = VS,

LDO2 is fully independent by LDO1 and keeps the normal activity

according to the behavior of an external voltage regulator

If LDO1 is in thermal shutdown,

also LDO2 is switched off

If LDO2 is in thermal shutdown,

LDO1 keeps the normal activity

OVERVOLTAGE/

THERMAL

WARNING

Events indicated respectively on the TW_LDO1 and TW_LDO2

pins

Events indicated respectively on the

TW_LDO1 and TW_LDO2 pins

If a cluster of the device detects a junction temperature above Twarn_LDO1,2, the relative advanced thermal

warning (TW_LDO1,2) pin is pulled low while the specific voltage regulator and its features are still active. The

TW_LDO1,2 pin returns to its high logic level (equal to VO_LDO1,2 output value) once the temperature falls below

the threshold Twarn_LDO1,2 - Twarn_hyst_LDO1,2.

Figure 46. Thermal warning diagram

When junction temperature reaches the Tprot shutdown threshold the device is quickly shuts-off through the

internal fast output discharge circuit; to be reactivated, junction temperature has to decrease below Tprot -

Tprot_hyst. Being TW_LDO1,2 open-drain outputs an external resistance (RTW) is needed between the

TW_LDO1,2 pins and the VO_LDO1,2 pins. The external resistance value can be in a range between 4.7 kΩ and

20 kΩ. Be aware that the current flowing through the TW_LDO1,2 pins drawn from VO_LDO1,2 when the

TW_LDO1,2 pins are pulled low may affect the watchdog activation/deactivation based on the regulator output

current consumption monitoring. Leave floating if not used.

4.8

Thermal clusters

To provide an advanced on-chip temperature control, the L99VR02XP outputs are split in two different

temperature clusters with dedicated thermal sensors; the sensors are suitably located on the device (see the

Figure 47). If the temperature of a cluster reaches the thermal protection threshold (Tprot), only the relevant output

is turned off while the other output remain active.

Thermal clusters can be configured according to the Table 16 using TC_CONF pin:

L99VR02XP

Application information

DS14686 - Rev 1

page 28/50

L99VR02XP 数据表(PDF) 28 Page - STMicroelectronics

L99VR02XP 数据表(HTML) 28 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

数据表下载