參數(shù)資料
型號(hào)： MAX2003A
廠(chǎng)商： Maxim Integrated Products, Inc.
元件分類(lèi)： 基準(zhǔn)電壓源/電流源
英文描述： Fast-Charge Battery Chargers(NICD/NIMH,可充電池?cái)?shù)1~16個(gè),電池快速充電器)
中文描述： 快速充電電池充電器（鎳鎘/鎳氫電池，可充電池?cái)?shù)1?16個(gè)，電池快速充電器）
文件頁(yè)數(shù)： 9/20頁(yè)
文件大小： 191K
代理商： MAX2003A
Battery Replacement
Before a battery is inserted, the BAT pin is pulled high-
er than the maximum cell voltage (MCV) by the resistor
(R
TR
) and the divider network (R
B1
/R
B2
) (Figure 1).
When the battery is inserted, the voltage per cell at BAT
falls from the default voltage to the battery voltage.
Fast-charge is initiated on a falling edge when the BAT
voltage crosses the voltage on MCV.
Applying Power to the MAX2003/MAX2003A
(battery already present)
There may be some cases where a battery is connect-
ed before power is applied to the MAX2003/
MAX2003A. When power is applied, the device goes
into reset mode for approximately 1.5sec and then
samples the CCMD and DCMD pins. Its charge status
is determined by the voltage at both the CCMD and
DCMD pins. Table 2 summarizes the various conditions
the MAX2003/MAX2003A might see on power-up.
Table 2 shows that the MAX2003/MAX2003A can be
set-up for fast-charge on power-up by making sure
CCMD and DCMD are at the same potential. If fast-
charge on power-up is not desired, make sure CCMD
and DCMD are at different logic levels during power-
up, and use a digital signal to control fast-charge (see
Digital Controlsection).
Digital Control
The CCMD pin can be used to initiate fast-charge. This is
useful when neither the power supply nor the battery can
be removed from the charger. The CCMD signal needed
to initiate fast-charge depends on the potential at DCMD.
If DCMD is low, a rising edge on CCMD initiates fast-
charge. If DCMD is high, a falling edge on CCMD pro-
vides the fast-charge signal. Table 3 summarizes the
conditions used to start fast-charge.
Disc harge-Before-Charge (optional)
The discharge-before-charge function is optional and
can be used to condition old batteries. It is especially
useful in NiCd batteries, since it alleviates the voltage
depression problems associated with partially dis-
charged NiCd cells. The discharge-before-charge
function is initiated by a rising edge into DCMD.
When the digital signal is applied, the DIS pin will be
pulled high, turning on the attached circuit and dis-
charging its battery. The discharge process continues
until the single cell voltage drops below 0.2V
CC
. During
the discharge phase, the CHG pin will be low (LED on)
for 1.375sec and high (LED off) for 0.125sec.
The MAX2003/MAX2003A does not control the current
during discharge-before-charge. If the discharge rate
is too great, the battery could overheat and be dam-
aged. The battery manufacturer will be able to specify
a safe discharge rate, but a rate of C or slower is typi-
cally acceptable. It is also important to choose compo-
nents (Q2, R
DIS
) that are rated for that particular
discharge rate. Since the gate-source drive for Q2 can
be as low as 4.5V, use a logic-level MOSFET.
Fast-Charge Current
The fast-charge current can be generated using two
categories of circuits:
Circuits with a sense resistor (R
SNS
)
Circuits without sense resistor (SNS tied to V
SS
)
Circuits with SNS Resistor
The standard application circuit of Figure 1 uses an
inductor and a switched mode of operation to supply
the current. The charge current is determined by the
sense resistor placed between the negative terminal of
the battery (SNS) and ground (V
SS
).
The SNS pin is the input to a comparator with hystere-
sis. If the voltage at SNS drops below 0.044V
CC
, the
MOD pin is turned on. If the SNS voltage is above
0.050V
CC
, MOD is turned off. In the switched mode of
operation, the SNS voltage ramps between 0.044V
CC
and 0.050V
CC
, which is 220mV and 250mV when V
CC
M
NiCd/NiMH Battery Fast-Charge Controllers
_______________________________________________________________________________________
9
Table 2. Device Status on Power-Up if
Battery is Already Present
MAX2003/MAX2003A Status when
DCMD
Table 3. Digital Control of Fast-Charge
(V
CC
and battery present)
The device does not enter fast-charge
immediately.
Fast-charge is initiated by the rising
edge of a pulse on CCMD.
Fast-charge is initiated on power-up.
Low
High
High
High
The device does not enter fast-charge
immediately.
Fast-charge is initiated by the falling
edge of a pulse on CCMD.
High
Low
CCMD
Fast-charge is initiated on power-up.
Low
Low
Power is Applied
Fast-charge is initiated by a falling
edge on CCMD.
High
CCMD
Fast-charge is initiated by a rising
edge on CCMD.
Low
CCMD Status to Initiate Fast-Charge
DCMD
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相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
MAX2003AC/D 制造商:MAXIM 制造商全稱(chēng):Maxim Integrated Products 功能描述:NiCd/NiMH Battery Fast-Charge Controllers
MAX2003ACPE 制造商:Maxim Integrated Products 功能描述:
MAX2003ACSE 制造商:Rochester Electronics LLC 功能描述: 制造商:Maxim Integrated Products 功能描述:
MAX2003ACWE 制造商:MAXIM 制造商全稱(chēng):Maxim Integrated Products 功能描述:NiCd/NiMH Battery Fast-Charge Controllers
MAX2003ACWE+ 制造商:Rochester Electronics LLC 功能描述: 制造商:Maxim Integrated Products 功能描述:
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