a5975d STMicroelectronics, a5975d Datasheet - Page 11

• Manufacturer Part Number: a5975d
• Description: Up To 3 A Step-down Switching Regulator For Automotive Applications
• Manufacturer: STMicroelectronics

A5975D
5
Figure 3.
Functional description
The main internal blocks are shown in the device block diagram in
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Block diagram
A voltage regulator supplying the internal circuitry. From this regulator, a 3.3 V
reference voltage is externally available
A voltage monitor circuit which checks the input and the internal voltages
A fully integrated sawtooth oscillator with a frequency of 250 kHz ± 15%, including also
the voltage feed-forward function and an input/output synchronization pin
Two embedded current limitation circuits which control the current that flows through
the power switch. The pulse-by-pulse current limit forces the power switch OFF cycle-
by-cycle, if the current reaches an internal threshold, while the frequency shifter
reduces the switching frequency in order to significantly reduce the duty cycle
A transconductance error amplifier
A pulse width modulator (PWM) comparator and the relative logic circuitry necessary to
drive the internal power
A high side driver for the internal P-MOS switch
An inhibit block for standby operation
A circuit to implement the thermal protection function
Doc ID 018760 Rev 1
Figure
Functional description
3. They are:
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