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LM2622

FB!

40.2k

10uH

2.2nF

24k

22UF

OUT

22uF

FB2

7.5k

SHDN

FSLCT

GND

2.7V - 3.3V

Battery or

Power

Source

LM2622

www.ti.com

SNVS068E –MAY 2000–REVISED MARCH 2013

LM2622 600kHz/1.3MHz Step-up PWM DC/DC Converter

Check for Samples: LM2622

FEATURES

DESCRIPTION

The LM2622 is a step-up DC/DC converter with a

• 1.6A, 0.2Ω, Internal Switch

1.6A, 0.2Ω internal switch and pin selectable

• Operating Voltage as Low as 2.0V

operating frequency. With the ability to convert 3.3V

• 600kHz/1.3MHz Pin Selectable Frequency

to multiple outputs of 8V, -8V, and 23V, the LM2622

Operation

is an ideal part for biasing TFT displays. The LM2622

can be operated at switching frequencies of 600kHz

• Over Temperature Protection

and 1.3MHz allowing for easy filtering and low noise.

• 8-Lead VSSOP Package

An external compensation pin gives the user flexibility

in setting frequency compensation, which makes

APPLICATIONS

possible the use of small, low ESR ceramic

capacitors at the output. The LM2622 is available in a

• TFT Bias Supplies

low profile 8-lead VSSOP package.

• Handheld Devices

• Portable Applications

• GSM/CDMA Phones

• Digital Cameras

Typical Application Circuit

Figure 1. 600 kHz Operation

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.

2All trademarks are the property of their respective owners.

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 (26 pages)

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LM2622 www.ti.com SNVS068E – MAY 2000 – REVISED MARCH 2013 LM2622 600kHz/1.3MHz Step-up PWM DC/DC Converter Check for Samples: LM2622 FEATURES DESCRIPTION • • • The LM2622 is a step-up DC/DC converter with a 1.6A, 0.2Ω internal switch and pin selectable operating frequency. With the ability to convert 3.3V to multiple outputs of 8V, -8V, and 23V, the LM2622 is an ideal part for biasing TFT displays. The LM2622 can be operated at switching frequencies of 600kHz and 1.
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LM2622 SNVS068E – MAY 2000 – REVISED MARCH 2013 www.ti.com Connection Diagram 1 8 VC NC FB FSLCT 2 7 3 SHDN VIN GND SW 4 6 5 Figure 2. Top View 8-Lead Plastic VSSOP See DGK Package Pin Description 2 Pin Name 1 VC Compensation network connection. Connected to the output of the voltage error amplifier. Function 2 FB Output voltage feedback input. 3 SHDN 4 GND Analog and power ground. 5 SW Power switch input. Switch connected between SW pin and GND pin.
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LM2622 www.ti.com SNVS068E – MAY 2000 – REVISED MARCH 2013 Block Diagram FSLCT ¦ 85% Duty Cycle Limit Oscillator Load Current Measurement SW + PWM COMP - - FB BG Set Reset Reset Drive Driver LOGIC ERROR AMP OVP + BG Thermal UVP SD OVP COMP + BG + Internal Supply Thermal Shutdown Bandgap Voltage Reference VC Shutdown Comparator SHDN UVP COMP VIN GND These devices have limited built-in ESD protection.
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LM2622 SNVS068E – MAY 2000 – REVISED MARCH 2013 www.ti.com (1) (2) Absolute Maximum Ratings VIN 12V SW Voltage 18V FB Voltage 7V VC Voltage 7V SHDN Voltage 7V FSLCT 12V Maximum Junction Temperature Power Dissipation 150°C (3) Internally Limited Lead Temperature 300°C Vapor Phase (60 sec.) 215°C Infrared (15 sec.) 220°C ESD Susceptibility (4) Human Body Model 2kV Machine Model (1) 200V Absolute maximum ratings are limits beyond which damage to the device may occur.
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LM2622 www.ti.com SNVS068E – MAY 2000 – REVISED MARCH 2013 Electrical Characteristics (continued) Specifications in standard type face are for TJ = 25°C and those with boldface type apply over the full Operating Temperature Range ( TJ = −40°C to +125°C)Unless otherwise specified. VIN =2.0V and IL = 0A, unless otherwise specified.
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LM2622 SNVS068E – MAY 2000 – REVISED MARCH 2013 www.ti.com Typical Performance Characteristics 6 Efficiency vs. Load Current (VOUT = 8V, fS = 600 kHz) Efficiency vs. Load Current (VOUT = 8V, fS = 1.3 MHz) Figure 3. Figure 4. Switch Current Limit vs. Temperature (VIN = 3.3V, VOUT = 8V) Switch Current Limit vs. VIN Figure 5. Figure 6. RDSON vs. VIN (ISW = 1A) IQ vs. VIN (600 kHz, not switching) Figure 7. Figure 8.
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LM2622 www.ti.com SNVS068E – MAY 2000 – REVISED MARCH 2013 Typical Performance Characteristics (continued) IQ vs. VIN (600 kHz, switching) IQ vs. VIN (1.3 MHz, not switching) Figure 9. Figure 10. IQ vs. VIN (1.3 MHz, switching) IQ vs. VIN (In shutdown) Figure 11. Figure 12. Frequency vs. VIN (600 kHz) Frequency vs. VIN (1.3 MHz) Figure 13. Figure 14.
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LM2622 SNVS068E – MAY 2000 – REVISED MARCH 2013 www.ti.com Typical Performance Characteristics (continued) Load Transient Response (600 kHz operation) Test circuit is shown in Figure 20. Figure 15. 8 Load Transient Response (1.3 MHz operation) Test circuit is shown in Figure 21 Figure 16.
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LM2622 www.ti.com SNVS068E – MAY 2000 – REVISED MARCH 2013 OPERATION L D COUT VIN RLOAD PWM L X + + L COUT VIN RLOAD V IN COUT R LOAD V OUT V OUT - - Cycle 1 (a) Cycle 2 (b) (a) First Cycle of Operation (b) Second Cycle Of Operation Figure 17. Simplified Boost Converter Diagram CONTINUOUS CONDUCTION MODE The LM2622 is a current-mode, PWM boost regulator. A boost regulator steps the input voltage up to a higher output voltage.
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LM2622 SNVS068E – MAY 2000 – REVISED MARCH 2013 www.ti.com INTRODUCTION TO COMPENSATION IL (A) VIN VOUT L VIN L 'i L IL_AVG t (s) D*Ts Ts (a) ID (A) VIN VOUT L ID_AVG =IOUT_AVG t (s) D*Ts Ts (b) (a) Inductor current (b) Diode current Figure 18. The LM2622 is a current mode PWM boost converter. The signal flow of this control scheme has two feedback loops, one that senses switch current and one that senses output voltage.
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LM2622 www.ti.com fZC = fPC = SNVS068E – MAY 2000 – REVISED MARCH 2013 1 Hz 2SRCCC (3) 1 Hz 2S(RC + RO)CC where • RO is the output impedance of the error amplifier, approximately 1MegΩ (4) For most applications, performance can be optimized by choosing values within the range 5kΩ ≤ RC ≤ 20kΩ (RC can be up to 200kΩ if CC2 is used, see HIGH OUTPUT CAPACITOR ESR COMPENSATION) and 680pF ≤ CC ≤ 4.7nF.
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LM2622 SNVS068E – MAY 2000 – REVISED MARCH 2013 www.ti.com DC GAIN AND OPEN-LOOP GAIN Since the control stage of the converter forms a complete feedback loop with the power components, it forms a closed-loop system that must be stabilized to avoid positive feedback and instability. A value for open-loop DC gain will be required, from which you can calculate, or place, poles and zeros to determine the crossover frequency and the phase margin.
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LM2622 www.ti.com SNVS068E – MAY 2000 – REVISED MARCH 2013 SELECTING THE COMPENSATION COMPONENTS The first step in selecting the compensation components RC and CC is to set a dominant low frequency pole in the control loop. Simply choose values for RC and CC within the ranges given in the INTRODUCTION TO COMPENSATION section to set this pole in the area of 10Hz to 500Hz.
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LM2622 SNVS068E – MAY 2000 – REVISED MARCH 2013 www.ti.com L (D')2 Leff = (16) 2mc (no unit) n = 1+ m1 (17) (18) mc ≊ 0.072fs (in V/s) m1 # VINRDSON L (in V/s) where • • VIN is the minimum input voltage RDSON is the value chosen from the graph "RDSON vs. VIN " in the Typical Performance Characteristics section (19) LAYOUT CONSIDERATIONS The input bypass capacitor CIN, as shown in the typical operating circuit, must be placed close to the IC.
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LM2622 www.ti.com SNVS068E – MAY 2000 – REVISED MARCH 2013 Application Information D5 D4 C5 1uF C4 1uF VIN = 2.7V - 3.3V D6 L 10uH 23V D7 C6 1uF C7 1uF C1 4.7uF D1 D3 D2 -8V C2 0.1uF 5 SW 7 6 VIN FSLCT CFB1 0.1uF LM2622 RFB1 40.2k 8V 2 3 FB SHDN VC GND 1 CIN 10uF 4 RC 5.1k RFB2 7.5k CFB2* COUT1 10uF COUT2 10uF CC 3.9nF Figure 19.
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LM2622 SNVS068E – MAY 2000 – REVISED MARCH 2013 www.ti.com output, the voltage at C5 is 16V when referenced to ground. In the third stage, the 16V at C5 appears across C6 when the switch is closed. When the switch opens, C6 is referenced to the 8V output minus a diode drop, which raises the voltage at C6 with respect to ground to about 24V. Hence, in the fourth stage, C7 is charged to 24V when the switch is open.
PAGE 17
LM2622 www.ti.com SNVS068E – MAY 2000 – REVISED MARCH 2013 600 KHZ OPERATION L 10uH 2.7V - 3.3V D 5 6 SW VIN FSLCT 7 RFB! 40.2k LM2622 Battery or Power Source 3 FB SHDN VC CIN 22UF 2 8V GND 1 4 RC 24k RFB2 7.5k COUT 22uF CC 2.2nF Figure 20. 600 kHz operation 1.3 MHZ OPERATION L 4.7uH 2.7V - 3.3V D 5 6 SW VIN FSLCT 7 RFB! 160k LM2622 Battery or Power Source 3 CIN 33UF FB SHDN VC 2 8V GND 1 4 RC 56k RFB2 30k COUT 22uF CC 2.2nF Figure 21. 1.
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LM2622 SNVS068E – MAY 2000 – REVISED MARCH 2013 www.ti.com POWER DISSIPATION The output power of the LM2622 is limited by its maximum power dissipation. The maximum power dissipation is determined by the formula PD = (Tjmax - TA)/θJA where • • • Tjmax is the maximum specidfied junction temperature (125°C) TA is the ambient temperature θJA is the thermal resistance of the package (21) θJA is dependant on the layout of the board as shown below.
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LM2622 www.ti.
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LM2622 SNVS068E – MAY 2000 – REVISED MARCH 2013 20 www.ti.
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LM2622 www.ti.com SNVS068E – MAY 2000 – REVISED MARCH 2013 REVISION HISTORY Changes from Revision D (March 2013) to Revision E • Page Changed layout of National Data Sheet to TI format ..........................................................................................................
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PACKAGE OPTION ADDENDUM www.ti.
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PACKAGE MATERIALS INFORMATION www.ti.com 23-Sep-2013 TAPE AND REEL INFORMATION *All dimensions are nominal Device LM2622MM-ADJ/NOPB Package Package Pins Type Drawing SPQ Reel Reel A0 Diameter Width (mm) (mm) W1 (mm) B0 (mm) K0 (mm) P1 (mm) W Pin1 (mm) Quadrant VSSOP DGK 8 1000 178.0 12.4 5.3 3.4 1.4 8.0 12.0 Q1 LM2622MMX-ADJ/NOPB VSSOP DGK 8 3500 330.0 12.4 5.3 3.4 1.4 8.0 12.
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PACKAGE MATERIALS INFORMATION www.ti.com 23-Sep-2013 *All dimensions are nominal Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm) LM2622MM-ADJ/NOPB VSSOP DGK 8 1000 210.0 185.0 35.0 LM2622MMX-ADJ/NOPB VSSOP DGK 8 3500 367.0 367.0 35.
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