Datasheet

ManualsBrandsTEXAS INSTRUMENTS ManualsPMICsPMIC - voltage regulators - DC DC switch controllers SOIC 8

8 GD1

5 GD2

7 VCC

6 GND

UCC25600

www.ti.com

SLUS846B –SEPTEMBER 2008– REVISED JULY 2011

8-Pin High-Performance Resonant Mode Controller

Check for Samples: UCC25600

FEATURES

DESCRIPTION

• Variable Switching Frequency Control

The UCC25600 high performance resonant mode

• Programmable Minimum Switching Frequency

controller is designed for dc-to-dc applications

With 4% Accuracy (3% accuracy at

utilizing resonant topologies, especially the LLC half

temperature range: -20°C to 105°C)

bridge resonant converter. This highly integrated

• Programmable Maximum Switching Frequency

controller implements frequency modulation control

• Programmable Dead Time for Best Efficiency

and complete system functions in only an 8-pin

• Programmable Soft-Start Time

package. Switching to the UCC25600 will greatly

simplify the system design, layout and improve time

• Easy ON/OFF Control

to market, all at a price point lower than competitive

• Over-Current Protection

16-pin device offerings.

• Over-Temperature Protection

The internal oscillator supports the switching

• Bias Voltage UVLO and OVP

frequencies from 40 kHz to 350 kHz. This high

• Integrated Gate Driver With 0.4-A Source and

accuracy oscillator realizes the minimum switching

0.8-A Sink Capability

frequency limiting with 4% tolerance, allowing the

• Operating Temperature Range: –40°C to 125°C

designer to avoid "over design" of the power stage

• SOIC 8-Pin Package

and, thus, further reducing overall system cost. The

programmable dead time enables zero-voltage

switching with minimum magnetizing current. This will

APPLICATIONS

maximize system efficiency across a variety of

• 100-W to 1-kW Power Supplies

applications. The programmable soft-start timer

• LCD, Plasma and DLP® TVs

maximizes design flexibility demanded by the varied

• Adaptors, Computing and ATX Power Supplies

requirements of end equipments utilizing a half bridge

topology. By incorporating 0.4-A source and 0.8-A

• Home Audio Systems

sink driving capability, a low cost, reliable gate driver

• Electronic Lighting Ballasts

transformer is a real option.

The UCC25600 delivers complete system protection

functions including over current, UVLO, bias supply

OVP and over temperature protection.

TYPICAL APPLICATION DIAGRAM

Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas

Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.

PRODUCTION DATA information is current as of publication date.

Products conform to specifications per the terms of the Texas

Instruments standard warranty. Production processing does not

necessarily include testing of all parameters.

Summary of content (24 pages)

PAGE 1
UCC25600 SLUS846B – SEPTEMBER 2008 – REVISED JULY 2011 www.ti.
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UCC25600 SLUS846B – SEPTEMBER 2008 – REVISED JULY 2011 www.ti.
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UCC25600 SLUS846B – SEPTEMBER 2008 – REVISED JULY 2011 www.ti.com ELECTRICAL CHARACTERISTICS over operating free-air temperature range, −40°C < TA < 125°C, TJ = TA, VCC = 12 V, GND = 0 V, RRT = 4.7 kΩ, RDT = 16.9 kΩ, CVCC = 1 μF, (unless otherwise noted) SYMBOL PARAMETER TEST CONDITIONS MIN TYP MAX UNITS Bias Supply (VCC) 1 1.5 2.5 5 7.5 100 400 Measured at VCC rising 9.9 10.5 11.1 UVLO turn-off threshold Measured at VCC falling 8.9 9.5 10.1 UVLO hysteresis Measured at VCC 0.
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UCC25600 SLUS846B – SEPTEMBER 2008 – REVISED JULY 2011 www.ti.com ELECTRICAL CHARACTERISTICS (continued) over operating free-air temperature range, −40°C < TA < 125°C, TJ = TA, VCC = 12 V, GND = 0 V, RRT = 4.7 kΩ, RDT = 16.9 kΩ, CVCC = 1 μF, (unless otherwise noted) SYMBOL PARAMETER TEST CONDITIONS MIN TYP MAX UNITS Peak Current Limit VOC1(off) Level 1 over current threshold – VOC rising 0.9 1 1.1 VOC2(off) Level 2 over current latch threshold – VOC rising 1.8 2.0 2.
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UCC25600 SLUS846B – SEPTEMBER 2008 – REVISED JULY 2011 www.ti.com DEVICE INFORMATION 8-Pin SOIC, Top View DT 1 8 GD1 RT 2 7 VCC OC 3 6 GND SS 4 5 GD2 TERMINAL FUNCTIONS TERMINAL NAME DT NO. 1 DESCRIPTION I/O I This pin sets the dead time of high-side and low-side switch driving signals. Connect a resistor to ground. With internal 2.25-V voltage reference, the current flowing through the resistor sets the dead time.
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UCC25600 SLUS846B – SEPTEMBER 2008 – REVISED JULY 2011 www.ti.com Block Diagram 2.25V T J 160oC/140oC DT + TSD Thermal ShutDown 1 OV + 10.5V 9.5V Dead time generator RDT 20V 18V UVLO + 7 VCC 2.5V Feed back RT 2 Ic 8 GD1 OSC Vss UVLO OV Q OC TSD SET VCC D 5 GD2 FAULT Q CLR 5uA 6 GND GD_Stop 6V 170uA OC OC SS 3 + 1V Vss 4 OC_latch Css + + 2V 1.
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UCC25600 SLUS846B – SEPTEMBER 2008 – REVISED JULY 2011 www.ti.com TYPICAL CHARACTERISTICS At VCC = 12 V, RRT = 4.7 kΩ, RDT = 16.9 kΩ, VSS = 5 V, VOC = 0 V; all voltages are with respect to GND, TJ = TA = 25°C, unless otherwise noted. BIAS SUPPLY CURRENT vs BIAS SUPPLY VOLTAGE SWITCHING FREQUENCY vs RT CURRENT 350 Fsw - Switching Frequency - kHz Ivcc - Bias Supply Current - mA 1 0.9 0.8 0.7 0.6 0.5 0.4 0.3 300 250 200 150 100 -40 °C OC Open 0.2 25 °C 50 0.
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UCC25600 SLUS846B – SEPTEMBER 2008 – REVISED JULY 2011 www.ti.com TYPICAL CHARACTERISTICS (continued) GATE DRIVE FALLING; VCC=15V 0.8 1.4 14 0.7 1.2 12 0.6 10 Gate Drive Voltage 0.5 1 10 8 0.8 6 0.6 4 0.4 2 0 -2 0 100 200 300 400 500 Gate Drive Source Current 8 6 0.3 4 0.2 0.2 2 0.1 0 0 0 -0.2 600 -2 0 200 400 600 -0.1 1000 800 Time - ns Time - ns Figure 5. Figure 6.
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UCC25600 SLUS846B – SEPTEMBER 2008 – REVISED JULY 2011 www.ti.com TYPICAL CHARACTERISTICS (continued) VCC OVER VOLTAGE THRESHOLD vs TEMPERATURE OVER CURRENT THRESHOLD vs TEMPERATURE 2.5 OVP Off Threshold - VCC Rising 21 Voc Over Current Threshold - V VCC Over Voltage Threshold - V 22 OVP On Threshold -VCC Falling 20 19 18 2 OC Off Threshold - Voc Rising OC On Threshold - Voc Falling 1.5 OC Latch Threshold - Voc Rising 1 0.
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UCC25600 SLUS846B – SEPTEMBER 2008 – REVISED JULY 2011 www.ti.com APPLICATION INFORMATION Principal of Operation The soft-switching capability, high efficiency and long holdup time make the LLC resonant converter attractive for many applications, such as digital TV, ac/dc adapters and computer power supplies. Figure 12 shows the schematic of the LLC resonant converter. Cr Lr n:1:1 Lm Figure 12. LLC Resonant Converter The LLC resonant converter is based on the Series Resonant Converter (SRC).
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UCC25600 SLUS846B – SEPTEMBER 2008 – REVISED JULY 2011 www.ti.com In this equivalent circuit, the Vge and Voe are the fundamental harmonics of the voltage generated by the half bridge and the voltage on the transformer primary side, respectively. These voltages can be calculated through Fourier analysis.
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UCC25600 SLUS846B – SEPTEMBER 2008 – REVISED JULY 2011 www.ti.com From Equation 8, when switching frequency is equal to resonant frequency, fn = 1 and converter voltage gain is equal to 1. Converter gain at different loads and inductor ratio conditions are shown in Figure 14 through Figure 17. M vs ƒn M vs ƒn 2 2 Qe = 0.1 Qe = 0.2 Qe = 0.5 Qe = 1 Qe = 2 Qe = 5 1.5 Qe = 0.1 Qe = 0.2 Qe = 0.5 Qe = 1 Qe = 2 Qe = 5 1.5 M M 1 1 0.5 0.5 0 0.1 0.5 1 1.5 0 0.1 2 0.5 1 fn 1.
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UCC25600 www.ti.com SLUS846B – SEPTEMBER 2008 – REVISED JULY 2011 Adjustable Dead Time Resonant half-bridge converter relies on the resonant tank current at MOSFETs turn-off to achieve soft switching and reduce switching loss. Higher turn-off current provides more energy to discharge the junction capacitor, while it generates more turn-off loss. Smaller turn-off current reduces turn-off loss, but it requires longer time to discharge MOSFETs junction capacitors and achieve soft switching.
PAGE 14
UCC25600 SLUS846B – SEPTEMBER 2008 – REVISED JULY 2011 www.ti.com Oscillator With variable switching frequency control, UCC25600 relies on the internal oscillator to vary the switching frequency. The oscillator is controlled by the current flowing out of RT pin.
PAGE 15
UCC25600 SLUS846B – SEPTEMBER 2008 – REVISED JULY 2011 www.ti.com Soft Start During start up and fault recovery conditions, soft start is always implemented to prevent excessive resonant tank current and ensure Zero-Voltage Switching (ZVS). During soft start, the switching frequency is increased. The soft-start time can be programmed by placing a capacitor from SS pin to ground. The soft-start pin also serves as an ON/OFF control pin of the device.
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UCC25600 SLUS846B – SEPTEMBER 2008 – REVISED JULY 2011 www.ti.com Burst-Mode Operation During light load condition, the resonant converter tends to increase its switching frequency and maintain the output voltage regulation. However, due to ringing caused by transformer parasitic capacitor and the rectification-diode-junction capacitors, the energy could be directly transferred to the load through these capacitors.
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UCC25600 SLUS846B – SEPTEMBER 2008 – REVISED JULY 2011 www.ti.com Over-Current Protection To prevent power stage failure under excessive load current condition, the UCC25600 includes an over-current protection function. With a dedicated OC pin, the power stage is shut down when OC pin voltage is above 1 V. Once the OC pin voltage becomes lower than 0.6 V, the gate driver recovers with soft start. To enhance system safety, the UCC25600 latches up the whole system when OC pin becomes above 2 V.
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UCC25600 SLUS846B – SEPTEMBER 2008 – REVISED JULY 2011 www.ti.com Gate Driver Half-bridge resonant converter is controlled by the nearly 50% duty cycle variable frequency square wave voltage. This allows the half bridge to be easily driven by the gate-driver transformer.
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PACKAGE OPTION ADDENDUM www.ti.
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PACKAGE MATERIALS INFORMATION www.ti.com 22-Sep-2011 TAPE AND REEL INFORMATION *All dimensions are nominal Device UCC25600DR Package Package Pins Type Drawing SOIC D 8 SPQ Reel Reel A0 Diameter Width (mm) (mm) W1 (mm) 2500 330.0 12.4 Pack Materials-Page 1 6.4 B0 (mm) K0 (mm) P1 (mm) 5.2 2.1 8.0 W Pin1 (mm) Quadrant 12.
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PACKAGE MATERIALS INFORMATION www.ti.com 22-Sep-2011 *All dimensions are nominal Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm) UCC25600DR SOIC D 8 2500 340.5 338.1 20.
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IMPORTANT NOTICE Texas Instruments Incorporated and its subsidiaries (TI) reserve the right to make corrections, enhancements, improvements and other changes to its semiconductor products and services per JESD46, latest issue, and to discontinue any product or service per JESD48, latest issue. Buyers should obtain the latest relevant information before placing orders and should verify that such information is current and complete.