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Circuit Descriptions, Abbreviation List, and IC Data Sheets

EN 204 JL2.1E AA9.

Stand-by Supply

The Stand-by Supply is based upon the "Fly Back Converter"

principle. A description of this principle can be found in the

FM2x Service Manuals.

Specifications

• Class D audio amplifier on same panel.

• Low profile.

• Full range (90 - 270 V

) and for all screen sizes (however

NOT exchangeable due to component diversity).

Outputs

• +5V2.

• +5V_SW (switched "off" in stand-by).

• V_TUN (Tuner voltage, switched "off" in stand-by).

Inputs

• 130-400 V

from the Mains Filter panel (1306).

• STANDBY_INFO from SSB (1M03).

• Over-voltage / safety protection from the Main Supply

(1307 -> 6150/51/53 -> 7150 -> 7505/09 -> 7560).

– Protection against over-voltage of the mains.

– Protection against short-circuit of mains elco’s with

doubler.

Interfacing between SSB and Main Supply

• +24V (or +12V) from MF supply (1304) to Display

(backlight) (1312, 1313, or 1314, 1315 or 1316, 1317).

• +12V from MF supply (1304) to SSB (1M46) and Ambient

Light circuit (1M10).

9.2.3 Start-up Sequence

Connect the Mains Voltage

1. A voltage of 130-400 V

(depends on region) will be

available at the Stand-by Supply panel.

2. The +5V2 becomes available for the SSB.

Close the Functional Switch

1. +5V2_RELAY_IO will be present (= supply for relay and

uP). A POR is generated.

2. If STANDBY bit is "low", the +5V_SW will be present for the

SSB.

3. The relay is closed.

4. The Main Supply will start up.

5. The +24V (+12V for Sharp displays) and the Audio Supply

becomes available.

6. +12V ready from MF panel -> +8V6 on Stand-by Supply

panel is ready to SSB

9.2.4 Power States

There are four different power states.

Figure 9-7 Power state diagram

• OUT: The set is OUT when the mains cord is disconnected.

When the mains cord is connected, the set goes to OFF or

to STANDBY state, depending on the last status in the

NVM. From all states, the set can be set to the OUT state

by disconnecting the mains cord or by a mains interruption.

• OFF: In the OFF state, the OTC is powered but is in low

power STANDBY state. No LEDs are "on", RC6 is ignored,

no EPG or P50 is possible, Proximity is set to "off", time

extraction is not started (if it was done before this state, the

clock stays running). This state can only be changed by the

tact switch; the set goes via SEMI-STANDBY to ON. From

all states, we can go to the OFF state by the tact switch.

• STANDBY: The set is in STANDBY if the STANDBY bit is

set. This state can change with the RC6 "on" command, for

EPG loading, P50 recording, for time extraction, or for

ambient light. The next state is SEMI-STANDBY and to ON

if the STANDBY bit is not set.

• SEMI-STANDBY: State between STANDBY or OFF and

ON state. All supply voltages are present, but the screen is

blanked.

• ON: set is ON.

Notes:

• In SEMI-STANDBY coming from STANDBY, the blue LED

is "on",

• In SEMI-STANDBY coming from ON, the red LED is "on".

9.2.5 POR Detection

Since the ON/OFF switch is always closed (not present any

more), there is no POR by starting up. The POR line is

connected to +5V2 and is always "high". Only when the mains

cord is reconnected, the Stand-by supply starts up, and the

POR line follows the start up of the 5V2

9.3 DC/DC Converters (on SSB)

9.3.1 Introduction

The LCD Supply and Stand-by Supply are the main power

supplies for this chassis. They deliver the following supply

voltages to the SSB (connector 1M46):

• +12VS.

• +8V6.

• +5V2.

•+5V.

•+VTUN.

As the VIPER and many other ICs on the SSB require low

supply voltages at high current (up to 3 A for the main

voltages), on board DC/DC converters are implemented.

The circuit on the SSP provides the 3.3 V, 2.5 V, and 1.2 V.

A DC/DC converter has the following advantages:

• The DC/DC converter is directly on the SSB near the

circuits that needs to be powered.

• Some circuits on the SSB need high current by low voltage,

so there is no risk to have power dips or voltage loss in

connections between the PSU and the SSB panel.

9.3.2 Block Diagram

Philips JL2.1E - Page 204

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