This post explains for the regulator.

The Part Number is Z1051PI, AOZ1051PI.

The function of this semiconductor is Synchronous Buck Regulator.

The package is SO-8 Pin Type

Manufacturer: Alpha & Omega Semiconductors

Preview images :

Description

The Z1051PI is a high efficiency, easy to use, 3 A synchronous buck regulator. The AOZ1051PI works from 4.5 V to 18 V input voltage range, and provides up to 3 A of continuous output current with an output voltage adjustable down to 0.8 V. The AOZ1051PI comes in an exposed pad SO-8 package and is rated over a -40 °C to +85 °C operating ambient temperature range.

Features

1. 4.5 V to 18 V operating input voltage range

2. Synchronous Buck: 70 mΩ internal high-side switch and 40 mΩ internal low-side switch (at 12 V)

3. Up to 95 % efficiency

4. External soft start

5. Output voltage adjustable to 0.8 V

6. 3 A continuous output current

7. 500 kHz PWM operation

8. Cycle-by-cycle current limit

9. Pre-bias start-up

10. Short-circuit protection

11. Thermal shutdown

Pinouts:

Applications:

1. Point of load DC/DC converters

2. LCD TV

3. Set top boxes

4. DVD and Blu-ray players/recorders

5. Cable modems

Z1051PI PDF Datasheet

A step-down switching regulator, also known as a buck converter, is an electronic circuit or device used in power electronics to convert a higher input voltage to a lower output voltage with high efficiency. It is a type of DC-DC converter widely used in various applications to efficiently regulate voltage levels.

Part Number: A6902D

Function: Up to 1 A Step Down Switching Regulator

Package: SO-8 Pin Type

Manufacturer: ST Microelectronics

Images:

Description

The A6902D is a complete step down switching regulator with adjustable current limit. Based on a voltage mode structure it integrates an additional current error amplifier to implement both a constant voltage and constant current control.

The current limit programming is very simple and accurate (± 5%) selecting the proper sensing resistor. The DC-DC converter can be used either as a voltage source with adjustable current
limit (set by using the external sense resistor) or as current source to charge NiMH / NiCd batteries or drive voltage load like LEDs.

Features

1. Qualified following the AEC-Q100 requirements

2. Up to 1 A DC output current

3. Operating input voltage from 8 V to 36 V

4. Output voltage adjustable from 1.235 V to 35 V

5. Precise 3.3 V (±2 %) reference voltage

6. 250 kHz Internally fixed frequency

7. Voltage feedforward

8. Zero-load current operation

9. Internal current limiting

10. Protection against feedback disconnection

11. Thermal shutdown

Pinouts:

Applications:

1. Automotive applications

2. Adjustable current generator

3. Simple step-down converters with adjustable current limit […]

 

A6902D PDF Datasheet