DS12548 Rev 3

11/20

L5050S

Protection features

19

3

Protection features

3.1

Voltage regulator

Voltage regulator uses a p-channel MOS transistor as a regulating element. With that

structure, a very low dropout voltage at current up to 50mA is obtained. The output voltage

is regulated up to transient input supply voltage of 40 V. The high-precision of the output

voltages (±2%) is obtained with a pre-trimmed reference voltage. The voltage regulator

automatically adapts its own quiescent current to the output current level. In light load

conditions, the quiescent current goes down to 50 µA only in low consumption mode. This

procedure features a certain hysteresis on the output current (see Figure 8). Short-circuit

protection to GND and a thermal shutdown are provided.

Figure 18. Application schematic – L5050S

The input capacitor C1 is necessary as backup supply for short battery voltage interruption

which may occur on the line. Its value should be chosen according to the relevant

capacitor, connected to the output pin, is for bypassing to GND the high-frequency noise

and it guarantees stability even during sudden line and load variations. Suggested value is

Stability region is reported in Figure 19.

Figure 19. Stability region

L5050S

C2

En1

GND1

C0

VBAT

C1

0.01

0.1

1

10

0.22

0.47

1

2.2

3.3

4.7

10

Co (µF)

ESR min

STABILITY REGION

UNTESTED REGION