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GENERAL DESCRIPTION

The ALD8100xx and ALD9100xx family of Supercapacitor Auto Balancing

MOSFETs, or SAB™ MOSFETs, are EPAD

address leakage balance of supercapacitors connected in series.

Supercapacitors, also known as ultracapacitors or supercaps, when con-

nected two in series, can be balanced with an ALD9100xx dual package.

Supercaps connected two, three or four in series can be balanced with an

ALD8100xx quad package.

ALD SAB MOSFETs have unique electrical characteristics for active con-

tinuous leakage current regulation and self-balancing of stacked series-

connected supercaps and, at the same time, dissipate near zero leakage

currents, practically eliminating extra power dissipation. For many

applications, SAB MOSFET automatic charge balancing offers a simple,

economical and effective method to balance and regulate supercap

voltages. With SAB MOSFETs, each supercap in a series-connected stack

is continuously and automatically controlled for precision effective supercap

leakage current and voltage balancing.

SAB MOSFETs offer a superior alternative solution to other passive

resistor-based or operational amplifier based balancing schemes, which

typically contribute continuous power dissipation due to linear currents at

all voltage levels. They are also a preferred alternative to many other

active supercap charging and balancing regulator ICs where tradeoffs in

cost, efficiency, complexity and power dissipation are important design

considerations.

The SAB MOSFET provides regulation of the voltage across a supercap

cell by increasing its drain current exponentially across the supercap when

supercap voltages increase, and by decreasing its drain current

exponentially across the supercap when supercap voltages decrease.

When a supercap in a supercap stack is charged to a voltage less than

90% of the desired voltage limit, the SAB MOSFET across the supercap

is turned off and there is zero leakage current contribution from the SAB

MOSFET. On the other hand, when the voltage across the supercap is

over the desired voltage limit, the SAB MOSFET is turned on to increase

its drain currents to keep the over-voltage from rising across the supercap.

However, the voltages and leakages of other supercaps in the stack are

lowered simultaneously to maintain near-zero net leakage currents.

The ALD8100xx/ALD9100xx SAB MOSFET family offers the user a se-

lection of different threshold voltages for various supercap nominal volt-

age values and desired leakage balancing characteristics. Each SAB

MOSFET generally requires connecting its V+ pin to the most positive

voltage and its V- and IC pins to the most negative voltage within the

package. Note that each Drain pin has an internal reverse biased diode

to its Source pin, and each Gate pin has a reverse biased diode to V-. All

other pins must have voltages within V+ and V- voltage limits. Standard

ESD protection facilities and handling procedures for static sensitive de-

vices must also be used.

APPLICATIONS

• Series-connected supercapacitor cell leakage balancing

• Energy harvesting

• Zero-power voltage divider at selected voltages

• Matched current mirrors and current sources

• Zero-power mode maximum voltage limiter

• Scaled supercapacitor stacks and arrays

ALD810023/ALD810024/ALD810025/

ALD810026/ALD810027/ALD810028

*IC pins are internally connected, connect to V-

SCL PACKAGES

PIN CONFIGURATION

ALD8100xx

* Contact factory for industrial temp. range or user-specified threshold voltage values.

Operating Temperature Range*

0°C to +70°C

16-Pin SOIC Package

ALD810023SCL

ALD810026SCL

ALD810024SCL

ALD810027SCL

ALD810025SCL

ALD810026SCL

FEATURES & BENEFITS

• Simple and economical to use

• Precision factory trimmed

• Automatically regulates and balances leakage currents

• Effective for supercapacitor charge-balancing

• Balances up to 4 supercaps with a single IC package

• Balances 2-cell, 3-cell, 4-cell series-connected supercaps

• Scalable to larger supercap stacks and arrays

• Near zero additional leakage currents

• Zero leakage at 0.3V below rated voltages

• Balances with series-connect and parallel-connect

• Leakage currents are exponential fuction of cell voltages

• Active current ranges from < 0.3nA to > 1000µA

• Always active, always fast response time

• Minimizes leakage currents and power dissipation

IC*

V-

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

IC*

V+

V-

V-

M2

M1

M4

M3

V-

V-