Saturday, June 01, 2019

L22DP03C, L22DP03U Hitachi LCD TV – Vestel 17MB29 chassis circuit descriptions and voltages

The system is a low to mid end; 22” 1680 x 1050 TFT TV solution basically for EU market with VCT4913G microcontroller / video audio processor chip on a 2-layer PCB. Since the target market is EU, the first release of the TV will support PAL/SECAM B/G/D/K/I/L/L’. The target panel is 22” W 1680 x 1050 TFT-LCD panels. A DVD loader is used to read DVD content and a DVB-T module card is used to support DVB-T.
Inputs
• 1xTuner (both analog and DVB-T)
• 1xDVD
• 1xScart
• 1xPC (VGA)
• 2xHDMI (optional)
• 1xBack AV (optional)
• 1xSIDE YPBPR (optional)
Outputs
• Speaker (stereo, 2x4 Ω, 2x4Watt)
• Headphone (stereo) (optional)
• Audio line out (stereo and mono) (optional)
• DVD/DVB-T coaxial SPDIF out(optional)

The system uses 17MB29 chassis.
17MB29 main board consists of two major blocks. The first block is analog front-end and this block is handled by VCTI chip that is highly multifunctional. VCTI performs Tuner IF demodulation, CVBS, RGB, SVHS and audio input selection and processing. The audio processor (MSP) supports equalizer, tone control, volume control, AVL, surround effect etc. The video processor (VSP) handles video processing such as color standard detection and demodulation, picture alignment (brightness,
contrast, color etc.). The IC also has a teletext decoder with fastext memory. The processed video output is sent to MST-TSUMU38BF, scaler/deinterlacer in RGB format together with a composite sync.  The TV tuner is PLL controlled symmetrical IF output type. The IF signal is filtered by a single SAW filter. Inter-carrier sound demodulation is performed by the system. After the SAW filter block, IF signal is processed by VCTI IF demodulator. Audio signal is digitally filtered in the IF demodulator block. The same IF signal is buffered and sent to DVB-T module card, tdm1300.Since VCTI can handle all the audio processing, there is no need for additional audio processor solution on the board.

MSP has two audio inputs which are assigned to the Scart in L/R and Audio Switch L/R output.
MSP has three audio outputs which are assigned to the headphone amplifier L/R input, audio amplifier L/R input and Audio switch L/R input. The board employs MP7721 and TDA1308 to drive speaker and headphone outputs, respectively. Switching control for other audio inputs and outputs (HDMI, Back AV, PC, DVD, and DVB-T) is achieved by an I2C controlled audio switch (TEA6422).
MST-TSUMU38BF has two ADC inputs. First ADC input is assigned to the VCTI RGB output.
Other RGB/YPbPr inputs are multiplexed for the second ADC input. HDMI receiver ANX9021 analog output, VGA RGB input and the synchronization signals are multiplexed by a primary RGB switch (PI5V512). MST-TSUMU38BF has an embedded LVDS transmitter. There are three PWM output ports.
PWM0 is assigned to analog/digital dimming control for the backlight, PWM1 is used for backlight on/off and panel logic power supply on/off control and PWM2 is used to control PC/HDMI switch IC (PI5V512).
 Power stage
The DC voltages required at various parts of the chassis and inverters are provided by a main power supply unit and power interface board. IPS generates 12V and 5V DC supply. Power stage which is on-chasis generates +12V for audio amplifier and 5V stand by voltage and 33V, 12V, 5V, 3.3V and 1.8Vsupplies for other different parts of the chassis.
TDM1300 board has no tuner on it. Instead, the tuner of 17MB29 is used for both analogue and digital reception. Tuner is controlled by either the 17MB29 microcontroller (VCTI), or TDM1300 board microcontroller. The IF (intermediate frequency) output of the tuner is sent to TDM1300 board for digital reception.
LVDS connector
This product include AC-DC flyback converter, DC-DC converter and DC-AC half bridge converter. There are two option whose total output power are 52W and 55W. This system does not have PFC (Power Factor Correction) coil.
Microcontroller/Video&Audio Processor (VCT4913G)
VCTI49xy is composed of microcontroller, video proccessor, display and deflection processor, sound proccessor and IF blocks.
VCTI49xyl family has two package types; PSSDIP88 and PMQFP144. PSSDIP88 package is chosen because of its convenience in the soldering process. PSSDIP88 package has two versions; 1 and 2. PSSDIP88-2 package is the “pinning mirrorred” version of PSSDIP88-1 and is preferred to be used for layout compatibility.
Scaler/De-interlacer (MST-TSUMU38BF)
The TSUMU38BF is total solution graphics processing ICs for LCD displays with panel resolutions up to XGA and WXGA+ / SXGA+ respectively. They are configured with a high-speed integrated triple-ADC/PLL, a high quality display processing engine, and an integrated multi-purpose output display interface that can support all major panel interface formats. To further reduce system costs, the MST517A-M also integrates intelligent power management control capability for green-mode requirements and spread spectrum support for EMI management.
The TSUMU38BF also incorporates a new Dynamic Frame Rate(DFR) generator for the digital output video to the display panel that preserves the advantages of a fixed output clock rate , while eliminating the output end of frame short-line.
MST has a built-in OSD generator with 291 character font programmable RAM. OSD generator supports 2/4/8 multi-color fonts, 8/16/256 color palette and 1K code attributes.
Power pins
IC EEPROM 2Kbx8(24LC02)
The 24LC01/02 is a 1K/2K-bit serial read/write non-volatile memory device using the CMOS floating gate process.Its 1024/2048 bits of memory are organized into 128/256 words and each word is 8 bits. The device is optimized for use in many industrial and commercial applications where low power and low voltage operation are essential. Up to eight 24LC01/02 devices may be connected to the same two-wire bus.
SPDIF Switch (NLAST4599)
The NLAST4599 is an advanced high speed CMOS single pole - double throw analog switch fabricated with silicon gate CMOS technology. It achieves high speed propagation delays and low ON resistances while maintaining low power dissipation. This switch controls analog and digital voltages that may vary across the full power-supply range (from VCC to GND).
The device has been designed so the ON resistance (RON) is much lower and more linear over input voltage than RON of typical CMOS analog switches.
The channel select input structure provides protection when voltages between 0V and 5.5V are applied, regardless of the supply voltage. This input structure helps prevent device destruction caused by supply voltage - input/output voltage mismatch, battery backup, hot insertion, etc.
Main features of NLAST4599 are:
• Select Pin Compatible with TTL Levels
• Channel Select Input Over-Voltage Tolerant to 5.5V
• Fast Switching and Propagation Speeds
• Break-Before-Make Circuitry
• Low Power Dissipation: ICC = 2A (Max) at TA = 25°C
• Diode Protection Provided on Channel Select Input
• Improved Linearity and Lower ON Resistance over Input Voltage
• Latch-up Performance Exceeds 300mA
• ESD Performance: HBM > 2000V; MM > 200V
• Chip Complexity: 38 FETs