Tuesday, December 01, 2015

SAMSUNG LS17PEA - LS19PEB POWER SUPPLY CIRCUIT AND BACK LIGHT INVERTER CIRCUIT

Contents of this article 

  • Power Block digram 
  • Protection circuit
  • Power supply schematic diagram 


LCD MONITOR 

SAMSUNG LS17PEA - LS19PEB 

POWER SUPPLY CIRCUIT AND BACK LIGHT INVERTER CIRCUIT  

Overall Block Structure
Power

1. When the AD board is in DPMS state:
1.1 The IP has been designed so that it operates with a power consumption of less than 0.6W of.
1.2 The Scaler consumes power up to 37mA
1.3 The power to the panel is switched off
2. When the AD board is operating normally:
2.1 The maximum power consumption of the panel lamps is described below (It may vary depending on
the panel manufacturer)
17" : 4*(7.5mA*650mVrms)=4*4.9=19.6W
19: : 4*(7.5mA*720mVrms)=4*5.4=21.6W
2.2 The power consumption of the Panel Control board is as follows: 5V*720mA=3.6W
2.3 The power consumption of the Scaler is as follows: 3.3V*245mA + 1.8V*300mA = 1.35W
Main Board Parts
17 INCH

19 INCH

1. Inverter: A conversion device that converts DC rated voltage/current to high ones necessary for the panel lamp.
2. DC/DC(Regulator): General term for DC to DC converting devices.
The IP board receives 5V and outputs 1.8 or 3.3V that is supplied to the scaler (GM5726).
3. Power MosFET: The IP board receives 5V and outputs a lower voltage in DPMS mode and supplies the whole 5V for the panel operating board in normal conditions. In that case, the switching of Power MosFET is controlled by Micom.
4. Scaler: Receives the digital TMDS and analog
R,G,B signals and convert them to proper resolutions using up- or down- scaling that are transferred to the panel in the LDVS formats.
5. Crystal(Oscillator): Use one 14.318MHz oscillator externally to supply power to both MCU and Scaler at the same time.
6. SCALER & EEPROM: I2C is a two-way serial bus of two lines that supports communications across the integrated circuits as well as between FLASH and EEPROM. In particular, FLASH and Scaler (GM5726) use the SDR direct bus for mutual communications, which is an effective, speedy system because it allows 4 additional address/data lines compared to the old serial systems.
7. Function Key: A certain keystroke generates a certain electrical potential, which is transferred into ADC input port of the Scaler and then converted to a digital value by the A/D converter of the chip. The digital value (data) is a clue to which key is entered. In practical, the voltage levels are set as below.
IP BOARD BLOCK(POWER) Parts

IP BOARD BLOCK( INVERTER ) Parts

IP BOARD ( inverter ) PROTECTION Parts
Pebble INVERTER CONTROLER FAN7310 have 2-way of the PROTECTION MODE.
1. OVP[Over Voltage Protection] : If the Voltage of the series capacitors C10 & C15 is over the 2.0V, the Inverter latched-off.
2. OLP[Over Load Protection] : If the inverter output harness is opened(No-output current), the base of the Q1 turns on and chage the C9 ovter 2V and then, the Inverter latched off
POWER SUPPLY CIRCUIT 
BACK LIGHT INVERTER CIRCUIT 
CLICK ON THE IMAGES TO ZOOM IN