SMB218 查看數據表（PDF） - Summit Microelectronics

零件编号

产品描述 (功能)

生产厂家

SMB218

Six-Channel Programmable DC-DC Power Managers with Battery Charger

Summit Microelectronics 

PLEASE NOTE: The SMB118 has entered End-of-Life.

SMB118/218

GENERAL DESCRIPTION

The SMB118 and SMB218 are fully programmable

power supply and battery managers that regulate,

sequence, monitor, and margin, an entire power

subsystem while controlling the charging of a lithium-ion

battery pack. They feature 6 voltage outputs, consisting

of: three synchronous PWM “Buck” step-down

converters, one configurable PWM “Boost or Buck”

converter, one PWM “Boost” step-up converter, one Low

Dropout (LDO) linear regulator, and a fully

programmable Li-Ion battery charger.

The SMB118 and SMB218 regulate each of the six

output channels to an accuracy of ±1.5% (typical). The

output is individually programmed and can be

reprogrammed via the I2C interface. In addition, several

sophisticated power management functions are built-in.

The SMB118 and SMB218 are capable of power-on/off

cascade sequencing where each channel can be

assigned one of six sequence positions. Supplies may

also be individually powered on/off through an I2C

command or by assertion of the enable pin. Cascade

sequencing, unlike time based sequencing, uses

feedback to ensure that each output is valid before the

next channel is enabled.

Each output voltage and the battery are monitored for

under-voltage and over-voltage conditions, using a

comparator based scheme. In the event of a fault, all

supplies may be sequenced down or immediately

disabled. Multiple output status pins are provided to

notify host processors or other supervisory circuits of

system faults.

The SMB118 and SMB218 feature an Under-voltage

Lockout (UVLO) circuit to ensure the IC will not power up

until the battery voltage has reached a safe operating

voltage. The UVLO function exhibits hysteresis, ensuring

that noise on the supply rail does not inadvertently cause

faults on the internally regulated supply.

In the event of a system fault, all monitored supplies may

trigger fault actions such as power-off, or force-shutdown

operations. Each output on the SMB118 and SMB218

may also be turned off individually at any point through

an I2C command or by a programmable enable pin.

When used in portable applications, the devices are

powered from the main system battery. This input is

continuously monitored for under-voltage conditions.

There are two under-voltage settings for this supply;

both are user programmable and have a corresponding

status pin. When the first threshold level is reached, the

POWER_FAIL pin is asserted and latched. When the

second threshold level is reached on the main supply,

the nBATT_FAULT pin is asserted.

The SMB118 and SMB218 are equipped with three

synchronous Buck outputs and one “Buck-or-Boost”

output that use a 1MHz oscillator frequency. The

feedback circuitry on each step-down channel is

simplified by an internal programmable resistor divider

(Buck-or-Boost uses external resistor divider).

The SMB118 and SMB218 are equipped with one Boost

output that uses a 1MHz oscillator, and an asynchronous

topology reducing the necessity for an additional

external MOSFET driver. This Boost output also uses an

external p-channel sequencing MOSFET to isolate load

from the battery when not needed.

A Low Dropout (LDO) linear regulator with an adjustable

1.5V to 3.75V output provides a small dropout voltage

and ripple free supply that is optimal for “always on”

microcontrollers. The LDO has a separate input supply

pin.

The SMB118 and SMB218 provide margining control

over all of its output voltages. Through an I2C command,

all outputs can be margined by up to ±10% of the

nominal output voltage. 7-level dynamic voltage

management is also available for one of the channels. In

addition, each output is slew rate limited by soft-start

circuitry that is user programmable and requires no

external capacitors.

All programmable settings on the SMB118 and SMB218

are stored in non-volatile registers and are easily

accessed and modified over an industry standard I2C

serial bus. For fastest possible production times Summit

offers an evaluation card and a Graphical User Interface

(GUI).

Summit Microelectronics, Inc

2107 3.0 10/15/2008

2

Share Link: