In the below , we are going to see in detail 3v 5v ALW and LDO Section
Typical 3v 5v Always Voltage Section
This is the second section in the laptop motherboard called 3 volts and 5 volt section. This section receives adapter voltage and generates 3 volt to get power to SIO. This section is also called the Always Voltage section. It has two buck converters 3.3volt and 5volt. Also, it has two linear regulators called VREG3 and VREG5. If this section fails the laptop can’t turn on.
3v 5v ALW Section Signals And Their Descriptions
The following is the list of signals and their descriptions for the laptop CPU VRM section :
| SIGNAL NAME | DESCRIPTION |
|---|---|
| VIN | input supply to chip and MOSFET |
| VREG3 (LDO3) | linear 3 volt output |
| VREG5 (LDO5) | linear 5 volt output |
| UG And LG | UG = Upper MOSFET Triggering LG = Lower MOSFET Triggering |
| 3ON (EN) 5ON (EN) |
input to 3 volt and 5 volt enable signal |
| 3VALW 5VALW |
3.3 volt always voltage output 5 volt always voltage output |
| PGOOD | power good confirmation signal, which means power ok. |
Typical 3v 5v LDO Section
This is another type of 3 volt and 5 volt section. In this type of supply only one linear output that is 5 volt called LDO5 output and two Buck Converters for 3.3 volt and 5 volt.
3v 5v LDO Section Signals And Their Descriptions
The following is the list of signals and their descriptions for the laptop CPU VRM section :
| SIGNAL NAME | DESCRIPTION |
|---|---|
| VIN | input power to chip coming from adapter |
| LDOEN | LDO enable |
| LDO | linear 5 volt output |
| VCC | 5 volt input to the chip |
| ON3 ON5 |
Enable signal to the chip |
| 3.3v 5v |
3.3 volt and 5 volt output |
| PGOOD | power good signal output |
Diagnosing 3 Volt And 5 Volt Always Section
Below are the steps to follow for 3v 5v section
Check 18 volt coming
Firstly check whether 18 volt coming on VIN pin or not. If it’s not coming then check why it’s not coming.
Whether VREG3 = 3 volt and VREG5 = 5 volt
Check for VREG3 is coming approximately 3 volt and VREG5 approximately 5 volt. If they are not coming it means Chip may be bad or output circuit loading.
3 volt Enable Signal Is Coming
Check whether 3 volt enable signal is coming or not. If it’s not coming then check for Chip why not getting enable 3 volt.
Check output Coils for 3.3 volt and 5 volt output
Finally, check whether 3.3 volt and 5 volt coming on the output coil or not. If it is not coming then it can mean Chip or driving MOSFETs are bad.
This is how to learn how to solve problems for 3v 5v ALW and LDO Displaymonk.
Single Chip Buck Converter
This converter is very popularly used in Next Generation motherboards. Th this chip both switching MOSFET and PWM chip combine tother. There is one Linear regulated output for 3 volt or 5 volt and one PWM regulated output.
Single Chip 3 volt Always Voltage
| SIGNAL NAME | DESCRIPTION |
|---|---|
| VIN | input voltage to chip |
| LDO | linear voltage output |
| ENABLE | enable signal to PWM |
| OUTPUT | buck output voltage |
| PGOOD | power good signal |
Single Chip 3v 5v volt Always Voltage
| SIGNAL NAME | DESCRIPTION |
|---|---|
| VIN | input voltage to chip |
| LDO | linear voltage output |
| ENABLE | enable signal to PWM |
| OUTPUT | buck output voltage |
| PGOOD | power good signal |
You can learn about different laptop repairing related guides to make a good laptop repairman career. you can also contact us at 8087435056 via WhatsApp or via email use prasadbakare@gmail.com. Expect a reply in 2-3 days.
Thank you for your visit!!!