Functional description

L5973AD

10/21

Figure 5.

Current limitation circuitry

4.5

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 (1.235V), while the inverting input (FB) is connected to the external divider or

directly to the output voltage. The output (COMP) is connected to the external compensation

network.

The uncompensated error amplifier has the following characteristics:

The error amplifier output is compared with the oscillator sawtooth to perform PWM control.

DRIVER

NOT

A1

PWM

VCC

OUT

A1/A2=95

RSENSE

D00IN1134

I

I

RTH

A2

Table 5. Uncompensated error amplifier

Transconductance

2300

µS

Low frequency gain

65dB

Minimum sink/source voltage

1500

µA/300µA

Output voltage swing

0.4V/3.65V

Input bias current

2.5

µA