ST1S14 datasheet(13/46 Pages) STMICROELECTRONICS

13 / 46 page

DocID17977 Rev 2

13/46

ST1S14

Function description

4.4

Error amplifier

The voltage error amplifier is the core of the loop regulation. It is a transconductance

operational amplifier whose non inverting input is connected to the internal voltage

reference (1.222 V), while the inverting input (FB) is connected to the external divider or

directly to the output voltage.

The error amplifier is internally compensated to minimize the size of the final application.

The error amplifier output is compared with the inductor current sense information to

perform PWM control.

4.5

Inhibit function

The inhibit feature is used to set the device in standby mode according to Table 2. When the

device is disabled, the power consumption is reduced to less than 40 µA. The EN2 pin is

also VIN compatible.

4.6

Thermal shutdown

The shutdown block generates a signal that turns off the power stage if the temperature of

the chip goes higher than a fixed internal threshold (150±10 °C). The sensing element of the

chip is very close to the PDMOS area, ensuring fast and accurate temperature detection. A

hysteresis of approximately 15 °C keeps the device from turning on and off continuously.

Table 7. Uncompensated error amplifier characteristics

Description

Values

Transconductance

218 µS

Low frequency gain

93 dB

24 pF

211 pF

200 k

ST1S14 データシート(PDF) 13 Page - STMicroelectronics