Figure 42. Undervoltage lockout on output voltage

VS

VO

VUVLO_rise

VUVLO_fall

4.11

Functional safety management

Even if not designed as safety HW element, the device contains some features that can be used to support

application that need to fulfill functional safety requirements. Analysis of the IC’s capability to reach the required

safety level, should be made at system level under user responsibility.

The following device safety requirements have been considered for a typical application:

Table 14. Safety requirement

ID

Description

SR-001

Operation of the voltage regulator(s) is allowed till over temperature limit.

SR-002

Operation of voltage regulator(s) is enabled until programmed current limit is

reached.

SR-003

Output voltage of regulator(s) shall remain within programmed range when RST pin

is not asserted.

SR-004

Output voltage of regulator(s) shall remain within programmed range when square

wave at TW pin is not generated.

Based on above requirements list the following safety mechanism has been implemented:

Table 15. Implemented safety mechanism

ID

Description

SR covered

SM1

Thermal sensor acting by TW pin

SR-004

SM2

Overtemperature protection

SR-001

SM3

Limitation on maximum output current

SR-002

SM4

Output voltage VO monitoring for

undervoltage detection

SR-002

SM5

Output voltage VO monitoring for

overvoltage detection

SR-002

L99VR01

Functional safety management

DS13649 - Rev 3

page 26/47