Datasheet ADP1621 (Analog Devices)

link to page 1
Constant-Frequency, Current-Mode Step-Up DC-to-DC Controller Data Sheet ADP1621 FEATURES TYPICAL APPLICATION CIRCUIT V 92% efficiency (no sense resistor required) IN = 3.3V ±1.0% initial accuracy L1 4.7µH IC supply voltage range: 2.9 V to 5.5 V VOUT = 5V D1 Power-input voltage as low as 1.0 V 1A Capable of high supply input voltage (>5.5 V) C3 C4 PIN IN 1µF 0.1µF R1 R 10V 10V S 35.7kΩ with an external NPN or a resistor 80Ω 1% COUT1 COUT2 COUT3 CS 1µF 10µF 150µF V 10V 10V 6.3V IN UVLO and 35 mA shunt regulator ADP1621 R2 ×2 External slope compensation with 1 resistor 11.5kΩ SDSN 1% GATE M1 Programmable operating frequency COMP (100 kHz to 1.5 MHz) with 1 resistor PGND R Lossless current sensing for switch-node voltage <30 V COMP FREQ 9.09kΩ FB C2 GND 120pF C1 Resistor current sensing for switch-node voltage >30 V C 47µF COMP 1.8nF R 6.3V Synchronizable to external clock FREQ 31.6kΩ 1% Current-mode operation for excellent line and load transient responses AGND f
1
10 μA shutdown current OSC = 600kHz C1 = MURATA GRM31CR60J476M M1 = VISHAY Si7882DP
-00 0
C D1 = VISHAY SSA33L Current limit and thermal overload protection OUT3 = SANYO POSCAP 6TPE150M
09
L1 = TOKO FDV0630-4R7M
06
Soft start in 2048 clock cycles
Figure 1. High Efficiency Output Boost Converter in Lossless Mode, 3.3 V Input, 5 V Output (Bootstrapped)
Supported by ADIsimPower™ design t ool
The ADP1621 supply input voltage range is 2.9 V to 5.5 V,
APPLICATIONS
although higher input voltages are possible with the use of a
APD bias
small signal NPN pass transistor or a single resistor. The voltage
Portable electronic equipment
of the power input can be as low as 1 V for fuel cell applications.
Isolated dc-to-dc converter
The switching frequency is set by an external resistor over a range
Step-up/step-down dc-to-dc converter
of 100 kHz to 1.5 MHz and can be synchronized to an external
LED driver for laptop computer and navigation system
clock by using the SDSN pin. The shutdown quiescent current is
LCD backlighting
less than 10 μA. The ADP1621 has a thermal shutdown feature that shuts down the gate driver when the junction temperature
GENERAL DESCRIPTION
reaches approximately 150°C. The internal soft start circuit limits The ADP1621 is a fixed-frequency, pulse-width modulation inrush current at startup. The ADP1621 is available in the 10-lead (PWM), current-mode, step-up converter controller. It drives an MSOP lead-free package and is specified over the −40°C to +125°C external n-channel MOSFET to convert the input voltage to a junction temperature range. higher output voltage. The ADP1621 can also be used to drive
100
flyback, SEPIC, and forward converter topologies, either isolated
90
or nonisolated. The ADP1621 eliminates the use of a current-sense power
80 )
resistor by measuring the voltage drop across the on resistance of
% ( 70
the n-channel MOSFET. This technique, allowed up to a
ENCY
maximum voltage of 30 V at the switch node, maximizes
ICI F 60 F
efficiency and reduces cost. For switch-node voltages higher than
E
30 V or for more accurate current limiting, the CS pin can be
50
connected to a current-sense resistor in the source of the MOSFET.
40
The slope compensation is implemented by an external resistor, allowing a wide range of external components (inductors and
300.01 0.1 1 10
042 MOSFETs), and can be chosen for various switching frequencies 0-
LOAD CURRENT (A)
609 0 and input and output voltages. Figure 2. Efficiency of Circuit Shown in Figure 1
Rev. D Document Feedback Information furnished by Analog Devices is believed to be accurate and reliable. However, no responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other rights of third parties that may result from its use. Specifications subject to change without notice. No One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. license is granted by implication or otherwise under any patent or patent rights of Analog Devices. Tel: 781.329.4700 ©2006–2016 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners. Technical Support www.analog.com
Document Outline FEATURES APPLICATIONS GENERAL DESCRIPTION TYPICAL APPLICATION CIRCUIT TABLE OF CONTENTS REVISION HISTORY SIMPLIFIED BLOCK DIAGRAM SPECIFICATIONS ABSOLUTE MAXIMUM RATINGS THERMAL RESISTANCE ESD CAUTION PIN CONFIGURATION AND FUNCTION DESCRIPTIONS TYPICAL PERFORMANCE CHARACTERISTICS THEORY OF OPERATION CONTROL LOOP CURRENT-SENSE CONFIGURATIONS CURRENT LIMIT UNDERVOLTAGE LOCKOUT SHUTDOWN SOFT START INTERNAL SHUNT REGULATORS SETTING THE OSCILLATOR FREQUENCY AND SYNCHRONIZATION FREQUENCY APPLICATION INFORMATION: BOOST CONVERTER ADIsimPower DESIGN TOOL DUTY CYCLE SETTING THE OUTPUT VOLTAGE INDUCTOR CURRENT RIPPLE INDUCTOR SELECTION INPUT CAPACITOR SELECTION OUTPUT CAPACITOR SELECTION DIODE SELECTION MOSFET SELECTION LOOP COMPENSATION SLOPE COMPENSATION CURRENT LIMIT LIGHT LOAD OPERATION Discontinuous Conduction Mode Pulse-Skipping Modulation RECOMMENDED COMPONENT MANUFACTURERS LAYOUT CONSIDERATIONS EFFICIENCY CONSIDERATIONS EXAMPLES OF APPLICATION CIRCUITS STANDARD BOOST CONVERTER—DESIGN EXAMPLE BOOTSTRAPPED BOOST CONVERTER Low Input and High Output Boost Converter High Input Voltage Boost Converter Circuit SEPIC CONVERTER CIRCUIT LOW VOLTAGE POWER-INPUT CIRCUIT LED DRIVER APPLICATION CIRCUITS RELATED DEVICES OUTLINE DIMENSIONS ORDERING GUIDE