Philips DVD763SA/051 manual Loader/Mono Board, Primary Current Sensing, Under-voltage Protection

EN 68	9.	DVD763SA	Circuit Descriptions and List of Abbreviations
			9.3	Loader/Mono Board
		K
						Loader
		R
					DVDalas2+	Loader-interface
		2.5V		-END
		A		FRONT	HF	Iguana		Program
		CL 96532065_071.eps
					Buffer			Memory
		130799				(front-end
						processor)
		Figure 9-2 TL431
						I2S	S2B
This reference component has two functions:
• A very stable and accurate reference diode					HF	STi55XX		SMI
• A high gain amplifier.
								(SDRAM)
When the output voltage increases (due to a reduction in the				END		(back-end		EMI
load), the voltage across RSENSE-2 (R3290/R3291) increases						processor)
				-				(FLASH)
to above the internal reference voltage of 2.5V. The TL431 will				BACK
					PCM
conduct and the current through the opto-coupler will increase.
This results in an increase of the voltage at pin 4 of IC1, which					FURORE 2	Video		Others
will reduce the 'on' time of Q1 (FET 7125). In the event of an
					Audio
output voltage decrease (due to an increase in the load), the
control circuit will operate in the opposite way.
						Module
Primary Current Sensing						Interface
								CL 26532053_022.eps
The current through FET Q1 will result in a voltage drop across
								260402
RSENSE-1 (R3120-23). This line goes to pin 11 of IC7130,					Figure 9-3 Block Diagram Loader/Mono board
which is the current sense input. The higher the input voltage,
the more the primary current is limited. In this way, the
maximum output power of the power supply is limited.				The SD4.00_SA_CH (SACHI_4) is the 2nd generation Philips
				Architectural Standard Design of SACD mono board based on
Under-voltage Protection				Furore 2, and will be used in the new generation of SACD
If the supply voltage at pin 13 of IC7130 drops below 7.2V				players. It is designed in a multi-task way so that it can support
(typical), e.g. due to a shorted secondary voltage or excessive				the following optional main functions:
load, the drive pulse at pin 12 is disabled and the controller will				• SD4.00_SA_CH: Support SACD player with 5-disc
switch 'off'.					changer.
				• SD4.00_SA: Support SACD player with single-disc.
Over-voltage Protection				• SD4.00_CH: Support DVD player with 5-disc changer but
					without SACD playback.
An internal over-voltage protection circuitry continuously
				• SD4.00_SA_I2C: Support SACD player with single-disc
monitors the Vcc pin. If, after start-up, this voltage exceeds
					and I2C slave.
40V, the internal latch circuit is triggered, the output buffer is
disabled, and the SMPS goes into over-voltage protection.				The SD4.00_SA_CH (SACHI_4) module consist of the
Now a complete restart sequence is required.
				following key components:
Note: If the event of the over-voltage situation remains present,
				1. OPU: Mercury 2 Loader VAL6011/14 (slim type) for a
the SMPS will go in sequence of protection, start-up, protection
					single-disc SACD player, or DVD VAM6001/14 mechanism
and the cycle repeats. This effect is highly audible.
					for a 5-disc SACD changer.
				2. Front-end:M2 Basic Engine.
				3. Back-end:DVD Host Processor STi55xx and Furore 2
					SACD DSD/DST decoder.
				4.	Power supply: To convert the PSU voltages to the correct
					values.
				5. Reset circuit: This circuit that the booting of the several
					devices on the mono board takes place in the correct order.
			9.3.1 The Optical Pick-up Unit (OPU)
				The Mercury 2 Loader has an optical unit consisting of two
				lasers:
				• One for CD with a wavelength of 780 nm.
				• One for DVD with a wavelength of 650 nm.
				The TZA1033 (item 7105) controls the data from these lasers,
				and the supply to them.
			9.3.2 Front-end: the Servo Part
				The front-end consists of:
				•	The Loader interface
				•	The Servo Processor/Decoder