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参数资料
| 型号： | MAX1647 |
| 厂商： | Maxim Integrated Products, Inc. |
| 元件分类： | 基准电压源/电流源 |
| 英文描述： | Chemistry-Independent Battery Chargers |
| 中文描述： | 与化学类型无关的电池充电控制器 |
| 文件页数： | 16/24页 |
| 文件大小： | 161K |
| 代理商： | MAX1647 |
M
The synchronous rectifier may not be completely
replaced by a diode because the BST capacitor
charges while the synchronous rectifier is turned on.
Without the synchronous rectifier, the BST capacitor
may not fully charge, leaving the high-side MOSFET
with insufficient gate drive to turn on. However, the syn-
chronous rectifier may be replaced with a small MOS-
FET, such as a 2N7002, to guarantee that the BST
capacitor is allowed to charge. In this case, most of the
current at high currents is carried by the diode and not
by the synchronous rectifier.
Internal Regulator and Referenc e
The MAX1647 uses an internal low-dropout linear regula-
tor to create a 5.4V power supply (VL), which powers its
internal circuitry. VL can supply up to 20mA. A portion of
this current powers the internal circuitry, but the remain-
ing current can power the external circuitry. The current
used to drive the MOSFETs comes from this supply,
which must be considered when calculating how much
power can be drawn. To estimate the current required to
drive the MOSFETs, multiply the total gate charge of
each MOSFET by the switching frequency (typically
250kHz). The internal circuitry requires as much as 6mA
from the VL supply. To ensure VL stability, bypass the VL
pin with a 1μF or greater capacitor.
The MAX1647 has an internal ±2% accurate 3.9V refer-
ence voltage. An external reference can be used to
increase the charger’s accuracy. Use a 4.096V reference,
such as the MAX874, for compliance with the Intel/
Duracell smart-battery specification. Voltage-setting
accuracy is ±0.65%, so the total voltage accuracy is the
accuracy added to the reference accuracy. For 1% total
voltage accuracy, use a reference with ±0.35% or greater
accuracy. If the internal reference is used, bypass it with
a 0.1μF or greater capacitor.
MAX 1647 Logic
The MAX1647 uses serial data to control its operation. The
serial interface complies with the SMBus specification (see
System Management Bus Specification from Intel
Architecture Labs; http://www.intel.com/IAL/power-
mgm.html; Intel Architecture Labs: 800-253-3696).
Charger functionality complies with the Intel/Duracell
Smart Charger Specification for a level 2 charger.
The MAX1647 uses the SMBus Read-Word and Write-
Word protocols to communicate with the battery it is
charging, as well as with any host system that monitors
the battery to charger communications. The MAX1647
never initiates communication on the bus; it only
receives commands and responds to queries for status
information. Figure 7 shows examples of the SMBus
Write-Word and Read-Word protocols.
Chemistry-Independent
Battery Chargers
16
______________________________________________________________________________________
ACK
S
T
S
S
W
R
D8
D9
D10
D11
D12
D13
D14
D15
ACK
D0
D1
D2
D3
D4
D5
D6
D7
ACK
CMD0
CMD1
CMD2
CMD3
CMD4
CMD5
CMD6
CMD7
ACK
W
1
0
0
1
0
0
0
START
S
ACK
1
1
0
0
1
0
0
0
ACK
W
1
0
0
1
0
0
0
START
S
S
ACK
THERMISTOR_OR
BOLD LINE INDICATES THAT
THE MAX1647 PULLS SDA LOW
ChargingMode( ) = 0 x 12
ChargingVoltage( ) = 0 x 15
ChargingCurrent( ) = 0 x 14
AlarmWarning( ) = 0 x 16
ChargerStatus( ) = 0 x 13
THERMISTOR_COLD
THERMISTOR_HOT
THERMISTOR_UR
ALARM_INHIBITED
POWER_FAIL
BATTERY_PRESENT
AC_PRESENT
ACK
CHARGE_INHIBITED
MASTER_MODE
VOLTAGE_NOTREG
CURRENT_NOTREG
LEVEL_2
LEVEL_3
CURRENT_OR
VOLTAGE_OR
ACK
R
1
0
0
1
0
0
0
REPEATED
START
Figure 7. Write-Word and Read-Word Examples
相关PDF资料 |
PDF描述 |
|---|---|
| MAX1648 | Chemistry-Independent Battery Chargers |
| MAX1647-MAX1648 | Chemistry-Independent Battery Chargers |
| MAX1648ESE | Chemistry-Independent Battery Chargers |
| MAX1647EAP | Chemistry-Independent Battery Chargers |
| MAX1649CSA | 5V/3.3V or Adjustable, High-Efficiency, Low-Dropout, Step-Down DC-DC Controllers |
相关代理商/技术参数 |
参数描述 |
|---|---|
| MAX1647EAP | 功能描述:电池管理 RoHS:否 制造商:Texas Instruments 电池类型:Li-Ion 输出电压:5 V 输出电流:4.5 A 工作电源电压:3.9 V to 17 V 最大工作温度:+ 85 C 最小工作温度:- 40 C 封装 / 箱体:VQFN-24 封装:Reel |
| MAX1647EAP+ | 功能描述:电池管理 RoHS:否 制造商:Texas Instruments 电池类型:Li-Ion 输出电压:5 V 输出电流:4.5 A 工作电源电压:3.9 V to 17 V 最大工作温度:+ 85 C 最小工作温度:- 40 C 封装 / 箱体:VQFN-24 封装:Reel |
| MAX1647EAP+T | 制造商:Maxim Integrated Products 功能描述:CHGR MULTI-CHEM 4A 18V 20SSOP - Tape and Reel |
| MAX1647EAP-T | 制造商:Maxim Integrated Products 功能描述:CHEMISTRY-INDEPENDENT BATTERY CHARGERS - Tape and Reel |
| MAX1648ESE | 功能描述:电池管理 RoHS:否 制造商:Texas Instruments 电池类型:Li-Ion 输出电压:5 V 输出电流:4.5 A 工作电源电压:3.9 V to 17 V 最大工作温度:+ 85 C 最小工作温度:- 40 C 封装 / 箱体:VQFN-24 封装:Reel |
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