Datasheet

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FEATURES APPLICATIONS

DESCRIPTION

UCD8220

SLUS652D – MARCH 2005 – REVISED OCTOBER 2006

www.ti.com

DIGITALLY MANAGED PUSH-PULL ANALOG PWM CONTROLLERS

• Digitally Managed Switch Mode Power

• For Digitally Managed Power Supplies Using

Supplies

µ Cs or the TMS320 ™ DSP Family

• Push-Pull, Half-Bridge, or Full-Bridge

• Voltage or Peak Current Mode Control with

Converters

Cycle-by-Cycle Current Limiting

• Battery Chargers

• Clock input from Digital Controller to set

Operating Frequency and Max Duty Cycle

• Analog PWM Comparator

The UCD8220 analog pulse-width modulator device

• 2-MHz Switching Frequency

is used in digitally managed power supplies using a

• 110-V Input Startup Circuit and Thermal

microcontroller or the TMS320™ DSP family.

Shutdown (UCD8620)

UCD8220 ia a double-ended PWM controller

• Internal Programmable Slope Compensation

configured with push-pull drive logic.

• 3.3-V, 10-mA Linear Regulator

Systems using the UCD8220 device close the PWM

• DSP/ µ C Compatible Inputs

feedback loop with traditional analog methods, but

• Dual 4-A TrueDrive™ High Current Drivers

the UCD8220 controller includes circuitry to interpret

a time-domain digital pulse train. The pulse train

• 10-ns Typical Rise and Fall Times with 2.2-nF

contains the operating frequency and maximum duty

• 25-ns Input-to-Output Propagation Delay

cycle limit which are used to control the power supply

• 25-ns Current Sense-to-Output Propagation

operation. This eases implementation of a converter

Delay with high level control features without the added

complexity or possible PWM resolution limitations of

• Programmable Current Limit Threshold

closing the control loop in the discrete time domain.

• Digital Output Current Limit Flag

• 4.5-V to 15.5-V Supply Voltage Range

• Rated from -40C to 105C

Figure 1. UCD8220 Typical Simplified Push-Pull Converter Application Schematic

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.

2 TMS320, TrueDrive, PowerPAD are trademarks of Texas Instruments.

3 is a registered trademark of ~ Texas Instruments.

UNLESS OTHERWISE NOTED this document contains

PRODUCTION DATA information current as of publication date.

Products conform to specifications per the terms of Texas

Instruments standard warranty. Production processing does not

necessarily include testing of all parameters.

Summary of content (29 pages)

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UCD8220 www.ti.
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UCD8220 www.ti.com SLUS652D – MARCH 2005 – REVISED OCTOBER 2006 DESCRIPTION (continued) The UCD8220 can be configured for either peak current mode or voltage mode control. It provides a programmable current limit function and a digital output current limit flag which can be monitored by the host controller to set the current limit operation. For fast switching speeds, the output stage uses the TrueDrive™ architecture, which delivers rated current of 4 A into the gate of a MOSFET.
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UCD8220 www.ti.com SLUS652D – MARCH 2005 – REVISED OCTOBER 2006 These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foam during storage or handling to prevent electrostatic damage to the MOS gates.
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UCD8220 www.ti.com SLUS652D – MARCH 2005 – REVISED OCTOBER 2006 PACKAGING INFORMATION (1) PACKAGE SUFFIX θJC(°C/W) θJA(°C/W) POWER RATING TA = 70°C, TJ = 125°C (mW) RATING FACTOR ABOVE 70°C (mW/°C) PowerPad™ MSSOP-16 PWP 2.07 37.47 (1) 1470 27 QFN-16 RSA - - - - QFN-20 RGW - - - - PowerPad™ soldered to the PWB with TI recommended PWB as defined in TI's Application Report ( TI Literature Number SLMA002) with OLFM.
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UCD8220 www.ti.com SLUS652D – MARCH 2005 – REVISED OCTOBER 2006 ELECTRICAL CHARACTERISTICS VDD = 12 V, 4.7-F capacitor from VDD to AGND, 1 µF from PVDD to PGND, 0.22-F capacitor from 3V3 to AGND, TA = TJ = -40C to 105C, (unless otherwise noted). PARAMETER TEST CONDITIONS MIN TYP MAX 300 500 UNIT SUPPLY SECTION Supply current, OFF VDD = 4.2 V Supply current, ON (UCD8220), outputs not switching, CLK = low 2 3 A mA LOW VOLTAGE UNDERVOLTAGE LOCKOUT (UCD8220 only) VDD UVLO ON 4.25 4.5 4.
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UCD8220 www.ti.com SLUS652D – MARCH 2005 – REVISED OCTOBER 2006 ELECTRICAL CHARACTERISTICS (continued) VDD = 12 V, 4.7-F capacitor from VDD to AGND, 1 µF from PVDD to PGND, 0.22-F capacitor from 3V3 to AGND, TA = TJ = -40C to 105C, (unless otherwise noted). PARAMETER TEST CONDITIONS MIN TYP MAX 2.64 - - CS ≤ ILIM, ILOAD = 7 mA - - 0.
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UCD8220 www.ti.com SLUS652D – MARCH 2005 – REVISED OCTOBER 2006 FUNCTIONAL BLOCK DIAGRAMS 16 NC NC 1 15 NC CLK 2 14 VDD 3V3 Regulator and Reference 3V3 3 UVLO 13 PVDD 12 OUT1 DRIVE LOGIC 11 OUT2 ISET 4 PWM PWM CTRL 6 10 PGND AGND 5 CLF 7 CURRENT LIMIT CURRENT SENSE ILIM 8 9 CS Figure 4. UCD8220 TERMINAL FUNCTIONS PIN NUMBER UCD8220 PIN NAME I/O FUNCTION 16 I Clock. Input pulse train contains operating frequency and maximum duty cycle limit.
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UCD8220 www.ti.com SLUS652D – MARCH 2005 – REVISED OCTOBER 2006 PIN NUMBER UCD8220 PIN NAME I/O HTSSOP-16 (PWP) QFN-16 (RSA) PVDD 13 12 VDD 14 13 I - - I VIN FUNCTION Supply pin provides power for the output drivers. It is not connected internally to the VDD supply rail. The bypass capacitor for this pin should be returned to PGND. Supply input pin to power the control circuitry. Bypass the pin with at least 4.7 µF of capacitance, returned to AGND.
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UCD8220 www.ti.com SLUS652D – MARCH 2005 – REVISED OCTOBER 2006 TYPICAL CHARACTERISTICS (continued) 3V3 SHORT-CIRCUIT CURRENT vs TEMPERATURE SUPPLY CURRENT vs FREQUENCY (VDD = 5 V) 160 140 22.5 IDD − Supply Current − mA ISHORT_CKT − Short Circuit Current − mA 23.0 22.0 VDD = 4.75 V 21.5 VDD = 12 V 21.0 100 80 CLOAD = 4.7 nF 60 40 CLOAD = 2.2 nF 20.5 20 20.0 CLOAD = 1 nF 0 −50 −25 0 25 50 75 t − Temperature − °C 100 125 0 500 1000 Figure 7. f − Frequency − kHz Figure 8.
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UCD8220 www.ti.com SLUS652D – MARCH 2005 – REVISED OCTOBER 2006 TYPICAL CHARACTERISTICS (continued) SUPPLY CURRENT vs FREQUENCY (VDD = 12 V) SUPPLY CURRENT vs FREQUENCY (VDD = 15 V) 500 400 450 300 IDD − Supply Current − mA IDD − Supply Current − mA 350 CLOAD = 10 nF 250 CLOAD = 4.7 nF 200 150 100 400 CLOAD = 10 nF 350 300 CLOAD = 4.7 nF 250 200 150 CLOAD = 2.2 nF CLOAD = 2.
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UCD8220 www.ti.com SLUS652D – MARCH 2005 – REVISED OCTOBER 2006 TYPICAL CHARACTERISTICS (continued) OUTPUT RISE TIME vs SUPPLY VOLTAGE OUTPUT FALL TIME vs SUPPLY VOLTAGE 65 45 40 CLOAD = 10 nF tF − Output Fall Time − ns tR − Output Rise Time − ns 55 45 35 CLOAD = 4.7 nF 25 CLOAD = 2.2 nF 35 CLOAD = 10 nF 30 25 CLOAD = 4.7 nF 20 CLOAD = 2.2 nF 15 15 CLOAD = 1 nF 10 CLOAD = 1 nF 5 5 5 7.5 10 12.5 15 5 10 12.5 15 VDD − Supply Voltage − V Figure 16.
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UCD8220 www.ti.com SLUS652D – MARCH 2005 – REVISED OCTOBER 2006 TYPICAL CHARACTERISTICS (continued) DEFAULT CURRENT LIMIT THRESHOLD vs TEMPERATURE CS TO OUTx PROPAGATION DELAY vs TEMPERATURE 40 tPD − CS to OUTx Propagation Delay − ns 0.59 VCS − Current Limit Threshold − V 0.58 0.57 0.56 0.55 0.54 0.53 0.52 35 30 25 20 15 10 5 0 0.51 −50 −25 0 25 50 75 100 125 −50 −25 0 TJ − Temperature − °C 25 50 75 100 Figure 19. TJ − Temperature − °C Figure 20.
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UCD8220 www.ti.com SLUS652D – MARCH 2005 – REVISED OCTOBER 2006 TYPICAL CHARACTERISTICS (continued) UCD8220 START-UP BEHAVIOR AT VDD = 12 V UCD8220 SHUT-DOWN BEHAVIOR AT VDD = 12 V CLK = CTRL = 3V3 CLK = CTRL = 3V3 VDD (2 V/div) VDD (2 V/div) 3V3 (2 V/div) OUTx (2 V/div) 3V3 (2 V/div) OUTx (2 V/div) t − Time − 40 ms/div t − Time − 40 ms/div Figure 23. Figure 24.
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UCD8220 www.ti.com SLUS652D – MARCH 2005 – REVISED OCTOBER 2006 TYPICAL CHARACTERISTICS (continued) INTERNAL SLOPE COMPENSATION IN CMC vs TEMPERATURE OUTPUT RISE AND FALL TIME (VDD = 12 V, CLOAD = 10 nF) Output Voltage − 2 V/div Internal Slope Compensation in CMC - V/ms 0.146 Current Mode Slope, RISET = 100 k 0.144 0.142 0.140 0.138 0.136 0.134 t − Time − 40 ns/div −50 −25 0 25 50 75 100 125 TJ − Temperature − °C Figure 28. Figure 27. PWM OFFSET AT CTRL INPUT vs TEMPERATURE 0.
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UCD8220 www.ti.com SLUS652D – MARCH 2005 – REVISED OCTOBER 2006 APPLICATION INFORMATION Introduction The UCD8220 is a digitally managed analog PWM controller configured with push-pull drive logic. In systems using the UCD8220 device, the PWM feedback loop is closed using the traditional analog methods, but the UCD8220 includes circuitry to interpret a time-domain digital pulse train from a digital controller.
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UCD8220 www.ti.com SLUS652D – MARCH 2005 – REVISED OCTOBER 2006 (1) (2) Start up (3) Steady State (4) Current Limit (5) UVLO and REF OK* CLK CTRL RAMP* PWM* OUT CS CLF * - Internal signals Figure 30.
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UCD8220 www.ti.com SLUS652D – MARCH 2005 – REVISED OCTOBER 2006 Current Sensing and Protection 40 kW 20 kW 10 kW 2.5 kW Figure 31.
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UCD8220 www.ti.com SLUS652D – MARCH 2005 – REVISED OCTOBER 2006 Selecting the ISET Resistor for Voltage Mode Control 3V3 3V3 (3) R_ISET ISET (4) I_SC = (3.3 - 1.85) / (11 x R_ISET) Selecting the ISET Resistor for Voltage Mode Control with Voltage Feed forward R PWM + CTRL (6) 3V3 VIN R + TO CLEAR of PWM LATCH Figure 33 shows the nominal value of resistance to use for a desired clock frequency.
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UCD8220 www.ti.com SLUS652D – MARCH 2005 – REVISED OCTOBER 2006 Selecting the ISET Resistor for Peak Current Mode Control with Internal Slope Compensation 10.0 3V3 R_ISET R PWM - + R + TO CLEAR of PWM LATCH CTRL (6) 0.25 V OUT ON Cint 12 pF S1 OFF RISET − Slope − V/µs ISET (4) I_SC = 1.85 / (11 x R_ISET) 1.0 0.1 CS (9) S2 Figure 35.
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UCD8220 www.ti.com SLUS652D – MARCH 2005 – REVISED OCTOBER 2006 TrueDrive™ consists of pull-up/pull-down circuits with bipolar and MOSFET transistors in parallel. The peak output current rating is the combined current from the bipolar and MOSFET transistors. This hybrid output stage also allows efficient current sourcing at low supply voltages. Source/Sink Capabilities During Miller Plateau Large power MOSFETs present a large load to the control circuitry.
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UCD8220 www.ti.com SLUS652D – MARCH 2005 – REVISED OCTOBER 2006 REFERENCES 1. Power Supply Seminar SEM-1600 Topic 6: A Practical Introduction to Digital Power Supply Control, by Laszlo Balogh, Texas Instruments Literature No. SLUP224 2. Power Supply Seminar SEM−1400 Topic 2: Design And Application Guide For High Speed MOSFET Gate Drive Circuits, by Laszlo Balogh, Texas Instruments Literature No. SLUP133. 3. Technical Brief, PowerPad Thermally Enhanced Package, Texas Instruments Literature No. SLMA002 4.
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PACKAGE OPTION ADDENDUM www.ti.
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PACKAGE OPTION ADDENDUM www.ti.com 11-Apr-2013 In no event shall TI's liability arising out of such information exceed the total purchase price of the TI part(s) at issue in this document sold by TI to Customer on an annual basis.
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