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MAX17710

Energy-Harvesting Charger and Protector

19-5872; Rev 2; 12/12

THINERGY is a registered trademark of Infinite Power Solutions, Inc.

Simplified Operating Circuit

Ordering Information appears at end of data sheet.

For related parts and recommended products to use with this part,

refer to: www.maximintegrated.com/MAX17710.related.

General Description

The MAX17710 is a complete system for charging and

protecting micropower-storage cells such as Infinite Power

Solutions’ THINERGY

microenergy cells (MECs). The IC

can manage poorly regulated sources such as energy-

harvesting devices with output levels ranging from 1FW to

100mW. The device also includes a boost regulator circuit

for charging the cell from a source as low as 0.75V (typ).

An internal regulator protects the cell from overcharging.

Output voltages supplied to the target applications are

regulated using a low-dropout (LDO) linear regulator with

selectable voltages of 3.3V, 2.3V, or 1.8V. The output regu-

lator operates in a selectable low-power or ultra-low-power

mode to minimize drain of the cell. Internal voltage protec-

tion prevents the cell from overdischarging.

The device is available in an ultra-thin, 3mm x 3mm x

0.5mm 12-pin UTDFN package.

Applications

Features

S Integrated Power-Management IC for Energy

Storage and Load Management

S Lithium Charger

1nA Standby I

QBATT

625nA Linear Charging

1µW

Boost Charging

Lithium Cell Undervoltage Protection

Charger Overvoltage Shunt Protection

1.8V, 2.3V, or 3.3V LDO (150nA I

QBATT

)

Lithium Cell Output Buffering

Ultra-Thin, 3mm x 3mm x 0.5mm UTDFN Package

Powered/Smart Cards

Remote Wireless

Sensors

Memory and Real-Time

Clock Backup

Semiactive RFID Tags

Medical Devices

High-Temperature

Applications

Military/DoD and

Aerospace

Toys

EVALUATION KIT AVAILABLE

GND

PGND SEL1

CHG

SEL2

BATT

TEG, SOLAR,

OR OTHER

LOW-VOLTAGE

SOURCE

RF OR OTHER

HIGH-VOLTAGE

SOURCE

THINERGY

MEC101

PCKP

REG

LCE

LDO

CONTROL

SIGNALS

UNREGULATED

OUTPUT

REGULATED

OUTPUT

MAX17710

For pricing, delivery, and ordering information, please contact Maxim Direct at

1-888-629-4642, or visit Maxim Integrated’s website at www.maximintegrated.com.

Summary of content (18 pages)

PAGE 1
EVALUATION KIT AVAILABLE MAX17710 Energy-Harvesting Charger and Protector General Description Features The MAX17710 is a complete system for charging and protecting micropower-storage cells such as Infinite Power Solutions’ THINERGY® microenergy cells (MECs). The IC can manage poorly regulated sources such as energyharvesting devices with output levels ranging from 1FW to 100mW. The device also includes a boost regulator circuit for charging the cell from a source as low as 0.75V (typ).
PAGE 2
MAX17710 Energy-Harvesting Charger and Protector ABSOLUTE MAXIMUM RATINGS BATT to GND............................................................-0.3V to +6V CHG to GND............................................................-0.3V to +6V LX to PGND..............................................................-0.3V to +6V GND to PGND.......................................................-0.3V to +0.3V FB, AE, LCE, SEL1, SEL2, REG, PCKP to GND........................................-0.3V to VBATT + 0.
PAGE 3
MAX17710 Energy-Harvesting Charger and Protector ELECTRICAL CHARACTERISTICS (continued) (VCHG = +4.3V, Figure 1, TA = -40NC to +85NC, unless otherwise noted. Typical values are at TA = +25NC.) (Note 1) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS LINEAR LDO REGULATOR REG Voltage REG Voltage, LCE Mode (Note 3) VPCKP = 4.0V, IREG = 50FA, SEL1 = open 3.22 3.3 3.37 VPCKP = 4.0V, IREG = 50FA, SEL1 = GND 2.25 2.3 2.375 VPCKP = 4.0V, IREG = 50FA, SEL1 = BATT 1.75 1.8 1.9 VPCKP = 4.
PAGE 4
MAX17710 Energy-Harvesting Charger and Protector ELECTRICAL CHARACTERISTICS (continued) (VCHG = +4.3V, Figure 1, TA = -40NC to +85NC, unless otherwise noted. Typical values are at TA = +25NC.) (Note 1) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS BOOST REGULATOR CHG Regulation Voltage VBATT = 4.125V 4.3 4.5 4.7 V Frequency VBATT = 3.9V, VCHG = 3.95V 0.73 1 1.27 MHz Boost Turn-On Time FB Threshold tBOOST-ON Design guidance, typical only ns Rising (enable) 0.485 0.75 1.
PAGE 5
MAX17710 Energy-Harvesting Charger and Protector Table 1. Summary of Typical Quiescent Current vs. Operating Conditions NAME MODE CONDITIONS IQBATT (nA) IQCHG (nA) TOTAL QUIESCENT CURRENT (nA) Standby Cell Connection: Regulator outputs off, no charger present Cell connected to circuit during assembly 1 — 1 (from cell) Shutdown UVLO or Shutdown: Regulator outputs off, no charger present VBATT falls below 2.
PAGE 6
MAX17710 Energy-Harvesting Charger and Protector Typical Operating Characteristics (TA = +25°C, unless otherwise noted.) 5 VOLTS (V) AE 3 REG 9 8 7 4 4 CHG SOLAR 3 PCKP 1 TA = +85°C 6 5 TA = +25°C 4 2 2 MAX17710 toc03 LX IDD (nA) 5 10 MAX17710 toc02 6 MAX17710 toc01 6 VOLTS (V) IDD vs. VBATT OVERTEMPERATURE LCE AND AE AND SEL1 = GND BOOST STARTUP REGULATOR STARTUP 3 2 1 TA = -40°C 1 0 0 TIME (ms) 4 TIME (µs) IDD vs.
PAGE 7
MAX17710 Energy-Harvesting Charger and Protector Pin Configuration TOP VIEW BATT 1 CHG 2 FB 3 GND + 12 PCKP 11 LCE 10 REG 4 9 SEL1 LX 5 8 SEL2 PGND 6 7 AE MAX17710 EP UTDFN Pin Description PIN NAME 1 BATT Cell Input. Connect to the positive terminal of the cell without a bypass capacitor. 2 CHG Charge Input. The IC charges the cell from the power source applied to this pin. Connect to the output of the boost circuit or directly to a 4.21V or higher charge source.
PAGE 8
MAX17710 Energy-Harvesting Charger and Protector Block Diagram BATT PCKP 10µF LINEAR CHARGE AND IDEAL DIODE CONTROL THINERGY MEC101 OVERDISCHARGE AND UNDERVOLTAGE PROTECTION UNREGULATED OUTPUT MAX17710 REF CHG 0.1µF RF, SOLAR, OR OTHER HIGH-VOLTAGE SOURCE LOAD VDD OUTPUT LINEAR REG 1.0µF 5.3V SHUNT PROTECTION TO REJECT OVERCHARGE ZLLS410TA REG 3.3V/2.3V/1.8V SELECT SEL 1 BATT 1.
PAGE 9
MAX17710 Energy-Harvesting Charger and Protector Detailed Description remains active after the removal of the charge voltage. The state of this latch is off when initial power is applied to the BATT pin. Operation While charging, the device consumes approximately 625nA from the CHG source until the voltage on CHG exceeds 4.15V. Above 4.15V, the IC enters dropout and BATT quiescent current increases from 1nA to 450nA.
PAGE 10
MAX17710 Energy-Harvesting Charger and Protector Boost Regulator Operation driving FB below the FBOFF threshold, which disables the boost circuit. The process repeats after the harvest source capacitor is recharged. The device includes a simple boost regulator controller to support energy harvesting from low-voltage solar or thermoelectric generator (TEG) devices.
PAGE 11
MAX17710 Energy-Harvesting Charger and Protector CHG Capacitor The CHG pin capacitor should be minimized to 0.1FF for highest charge efficiency. However, when charging from a high-voltage source, at least 0.22FF is required for shunt stability. LX Inductor The LX pin inductor is not required for high-voltage charge sources. For low-voltage sources, a minimum inductor value of 0.68FH is required to prevent the maximum current rating of the LX pin from being exceeded.
PAGE 12
MAX17710 Energy-Harvesting Charger and Protector The C1 1nF capacitor acts as a voltage-level feed forward to increase the responsiveness of the divider circuit as the harvest source capacitor is discharged. The minimum voltage is defined as: CHG 0.1µF VHARVEST-OFF ~= VHARVEST-ON - (FBON - FBOFF) ZLLS410TA VHARVEST-OFF ~= VHARVEST-ON - 0.5V (typ) where VHARVEST-OFF is the lowest voltage of the harvest source capacitor during boost.
PAGE 13
MAX17710 Energy-Harvesting Charger and Protector The LDO becomes active when the AE pin is pulsed above or held above its logic-high threshold, but the regulator output is not immediately enabled. The device first charges the external capacitor on PCKP. When the voltage level on PCKP reaches 3.7V, the regulator output is enabled in high-current mode.
PAGE 14
MAX17710 Energy-Harvesting Charger and Protector 4.1V BATT 4.1V BATT 2.15V 0V 2.15V 0V 4.1V PCKP 4.1V 3.7V PCKP 0V 0V AE VOH-AE VOH-AE AE VOL-AE VOL-AE 3.3V REG UVLO 0V 0V a. NORMAL REGULATOR OUTPUT ENABLE SEQUENCE > tUVLO1 (5s typ) b. REGULATOR OUTPUT ENABLE FAIL DUE TO UVLO TIMEOUT 4.1V BATT 2.15V 0V 4.1V PCKP 2.15V BATT 4.1V 3.0V PCKP 0V 0V 3.3V REG 3.3V 0V 4.1V REG 0V > tUVLO2 (500µs typ) UVLO UVLO 0V 0V c.
PAGE 15
MAX17710 Energy-Harvesting Charger and Protector Regulator Voltage Selection The SEL1 pin selects at which voltage REG operates. Connect SEL1 to BATT for 1.8V operation, three-state for 3.3V operation, or connect to GND for 2.3V operation. Note that the voltage regulation value is latched when enabled. To change the regulation voltage point, the regulator must be disabled and then reenabled. See Table 3.
PAGE 16
MAX17710 Energy-Harvesting Charger and Protector Package Information For the latest package outline information and land patterns (footprints), go to www.maximintegrated.com/packages. Note that a “+”, “#”, or “-” in the package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing pertains to the package regardless of RoHS status. PACKAGE TYPE PACKAGE CODE OUTLINE NO. LAND PATTERN NO.
PAGE 17
MAX17710 Energy-Harvesting Charger and Protector Revision History REVISION NUMBER REVISION DATE 0 12/12 DESCRIPTION Initial release PAGES CHANGED — Maxim Integrated cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim Integrated product. No circuit patent licenses are implied. Maxim Integrated reserves the right to change the circuitry and specifications without notice at any time.
PAGE 18
MAX17710 Energy-Harvesting Charger and Protector Maxim Integrated 18