SAMSUNG UA40C5000QR POWER SUPPLY CIRCUIT - PD46AFOU-ZSM, BN44-00352A - HV9963 - UCC25600

SAMSUNG UA40C5000QR POWER SUPPLY CIRCUIT - PD46AFOU-ZSM, BN44-00352A - HV9963 - UCC25600

SAMSUNG PD46AFOU-ZSM, BN44-00352A

HV9963 Closed Loop LED Driver

The HV9963 is a current mode control LED driver IC designed to control single switch PWM converters (buck, boost, buck-boost or SEPIC) in a constant frequency mode. The controller uses a peak current-mode control scheme (with programmable slope compensation) and includes an internal transconductance amplifier to accurately control the output current over all line and load conditions. Multiple HV9963s can be synchronized to each other or to an external clock using the SYNC pin. The IC also provides a disconnect switch gate drive output, which can be used to disconnect the LEDs in case of a fault condition using an external disconnect FET. The 10V external FET drivers allow the use of standard level FETs. The low voltage 5.0V AVDD is used to power the internal logic and also acts as a reference voltage to set the current level.
The HV9963 includes an enhanced PWM dimming logic (patent pending) that enables very high PWM dimming ratios. HV9963 also provides a TTL compatible, low-frequency PWM dimming input that can accept an external control signal with a duty ratio of 0-100% and a frequency of up to a few tens of kilohertz.

Applications
RGB or white LED backlighting 

Battery powered LED lamps  

Other DC/DC LED drivers

Power Supply to the IC (VIN, PVDD and AVDD)
The HV9963 can be powered directly from its VIN pin that takes a voltage up to 40V. There are two linear regulators within the HV9963 – a 10V linear regulator (PVDD), which is used for the two FET drivers, and a 5.0V linear regulator (AVDD) which supplies power to the rest of the control logic. The IC also has a built in under-voltage lockout which shuts off the IC if the voltage at either VDD pin falls below its UVLO threshold. Both VDD pins must by bypassed by a low ESR capacitor (≥ 0.1µF) for proper operation

Current Sense (CS)
The current sense input is used to sense the source current of the switching FET. The CS input of the HV9963 includes a built in 100ns (minimum) blanking time to prevent spurious turn off due to the initial current spike when the FET turns on. The IC includes an internal resistor divider network, which steps down the voltage at the COMP pins by a factor of 12 (11R:1R). This voltage is used as the reference for the current sense comparators. Since the maximum voltage of the COMP pin is AVDD - 0.7V, this voltage determines the maximum reference current for the current sense comparator and thus the maximum inductor current.

Soft Start (SS)
Soft start of the LED current can be achieved by connecting a capacitor at the SS pin. The rate of rise of SS pin limits the LED current’s rate of rise. Upon start-up, the capacitance at the COMP network is being charged by the 200μA sourcing current of the transconductance amplifier. Without the soft-start function, this larger current would cause the COMP voltage to increase faster than the boost converter’s response time, causing overshoots in the LED current during start-up.

Over Voltage Protection
The HV9963 provides hysteretic over voltage protection allowing the IC to recover in case the LED load is disconnected momentarily.

Pin Description

Pin	Name	Description
1	VIN	This pin is the input of a 40V high voltage regulator, and should not be left unconnected. If a voltage at PVDD is being applied from an external power supply, the VIN and PVDD pins should be shorted.
2	PVDD	This pin is a regulated 10V supply for the two gate drivers (FLT and GATE). It must be bypassed with a low ESR capacitor to GND (at least 1.0μF).
3	GATE	This is the GATE driver output for the switching FET.
4	GND	Ground return for all the low power analog internal circuitry as well as the gate drivers. This pin must be connected to the return path from the input.
5	CS	This pin is used to sense the source current of the external power FET. It includes a built-in 100ns (min) blanking time.
6	HCP	This pin provides the hiccup timer in case of a fault. A capacitor at this pin programs the hiccup time.
7	RT	This pin sets the frequency of the power circuit. A resistor between RT and GND will program the circuit in constant frequency mode. The switching frequency is synchronized to the PWMD input and oscillator will turn on once PWMD goes high.
8	SYNC	This I/O pin may be connected to the SYNC pin of other HV9963 circuits and will cause the oscillators to lock to the highest frequency oscillator.
9	SS	This pin is used to provide soft start upon turn-on of the IC. A capacitor at this pin programs the soft start time.
10	AVDD	This is a power supply pin for all internal control circuits. This voltage is also used as the reference voltage both internally and externally. It must be bypassed with a low ESR capacitor to GND (at least 0.1μF).
11	FLT	This pin is used to drive an external disconnect FET which disconnects the load from the circuit during a fault condition or during PWM dimming to achieve a very high dimming ratio.
12	OVP	This pin provides the over voltage protection for the converter. When the voltage at this pin exceeds 1.25V, the gate output of the HV9963 is turned off and FLT goes low. The IC will turn on when the voltage at the pin goes below 1.125V.
13	PWMD	When this pin is pulled to GND (or left open), switching of the HV9963 is disabled. When an external TTL high level is applied to it, switching will resume.
14	COMP	Stable Closed loop control can be accomplished by connecting a compensation network between COMP and GND.
15	IREF	The voltage at this pin sets the output current level. The current reference can be set using a resistor divider from the AVDD pin. Connecting a voltage greater than 1.25V at this pin will disable the short circuit comparator.
16	FB	This pin provides output current feedback to the HV9963 by using a current sense resistor.

UCC25600 8-Pin High-Performance Resonant Mode Controller

Description
The UCC25600 high performance, resonant mode controller is designed for dc-to-dc applications using resonant topologies, especially the LLC half-bridge resonant converter. This highly integrated controller implements frequency modulation control and complete system functions in only an 8-pin package. Switching to the UCC25600 will greatly simplify the system design and layout, and improve time to market, all at a price point lower than competitive 16- pin device offerings.
The internal oscillator supports the switching frequencies from 40 kHz to 350 kHz. This high- accuracy oscillator realizes the minimum switching frequency limiting with 4% tolerance, allowing the designer to avoid over-design of the power stage and, thus, further reducing overall system cost. The programmable dead time enables zero-voltage switching with minimum magnetizing current. This maximizes system efficiency across a variety of applications. The programmable soft-start timer maximizes design flexibility demanded by the varied requirements of end equipment using a half-bridge topology. By incorporating a 0.4-A source and 0.8-A sink driving capability, a low cost, reliable gate driver transformer is a real option. The UCC25600 delivers complete system protection functions including overcurrent, UVLO, bias supply OVP, and overtemperature protection.

Applications
100-W to 1-kW Power Supplies
LCD, Plasma, and DLP® TVs
Adaptors, Computing, and ATX Power Supplies
Home Audio Systems
Electronic Lighting Ballasts

POWER SUPPLY SCHEMATIC DIAGRAM 

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