參數(shù)資料
型號: MAX6782TEC+T
廠商: MAXIM INTEGRATED PRODUCTS INC
元件分類: 電源管理
英文描述: Low-Power, 1% Accurate, Dual-/Triple-/Quad-Level Battery Monitors in Small TDFN and TQFN Packages
中文描述: 4-CHANNEL POWER SUPPLY SUPPORT CKT, QCC16
封裝: ROHS COMPLIANT, TQFN-16
文件頁數(shù): 5/17頁
文件大?。?/td> 166K
代理商: MAX6782TEC+T
Reference Output
The reference output can provide up to 1mA of output
current. The output is not buffered. Excessive loading
affects the accuracy of the thresholds. An external
capacitor is not required for stability and is stable for
capacitive loads up to 50pF. In applications where the
load or the supply can experience step changes, a
capacitor reduces the amount of overshoot (under-
shoot) and improves the circuit’s transient response.
Place the capacitor as close to the device as possible
for best performance.
Applications Information
Resistor-Value Selection
Choosing the proper external resistors is a balance
between accuracy and power use. The input to the volt-
age monitor, while high impedance, draws a small cur-
rent, and that current travels through the resistive
divider, introducing error. If extremely high resistor val-
ues are used, this current introduces significant error.
With extremely low resistor values, the error becomes
negligible, but the resistive divider draws more power
from the battery than necessary, and shortens battery
life. See Figure 6 and calculate the optimum value for
R1 using:
where eA is the fraction of the maximum acceptable
absolute resistive divider error attributable to the input
leakage current (use 0.01 for 1%), VBATT is the battery
voltage at which LBO should activate, and IL is the
worst-case IN_ leakage current, from the
Electrical
Characteristics. For example, for 0.5% error, a 2.8V
battery minimum, and 5nA leakage, R1 = 2.80M
.
Calculate R2 using:
where VINF is the falling threshold voltage from Table 2.
Continuing the above example, and selecting VINF =
0.5477V (10% hysteresis device), R2 = 681k
. There
are other sources of error for the battery threshold,
including resistor and input monitor tolerances.
Calculating an External Hysteresis
Resistive Divider (MAX6782–MAX6785)
To set the hysteresis, place a resistive divider from REF
to HADJ_ as shown in Figure 6. The resistive divider
sets voltage on HADJ_, which controls the falling thresh-
old (VINF) on the associated IN_ (the rising threshold
(VINR) is fixed). See Table 2. Calculate R3 using:
where eA is the fraction of the maximum acceptable
absolute resistive divider error attributable to the input
leakage current (use 0.01 for 1%), VREF is the refer-
ence output voltage, and IL is the worst-case HADJ_
leakage current. Calculate R4 using:
where VINF is the desired falling voltage threshold. To
calculate the percent hysteresis, use:
where VINR is the rising voltage.
Calculating an External
Hysteresis Resistive Divider
(MAX6786/MAX6787/MAX6788)
Setting the hysteresis externally requires calculating
three resistor values, as indicated in Figure 2. First cal-
culate R1 using:
and R20 using:
where R20 = R2 + RHYST determine the total resistive-
divider current, ITOTAL, at the trip voltage using:
Then, determine RHYST using:
where VHYST is the required hysteresis voltage.
Finally, determine R2 using:
R2 = R20 - RHYST
R
V
I
HYST
TOTAL
=
I
V
RR
TOTAL
BATT
=
+
120
R
VR
VV
as in the above example
TH
BATT
TH
20
1
=
×
(
)
R
eV
I
A
BATT
L
1 =
×
Hysteresis
VV
V
INR
INF
INR
%
()
100
R
VR
VV
INF
REF
INF
4
3
=
×
R
eV
I
A
REF
L
3 =
×
R
VR
VV
INF
BATT
INF
2
1
=
×
R
eV
I
A
BATT
L
1 =
×
MAX6782–MAX6790
Low-Power, 1% Accurate, Dual-/Triple-/Quad-Level
Battery Monitors in Small TDFN and TQFN Packages
______________________________________________________________________________________
13
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MAX6783TEA+T 功能描述:電池管理 Quad 1%-Accurate Battery Monitor RoHS:否 制造商:Texas Instruments 電池類型:Li-Ion 輸出電壓:5 V 輸出電流:4.5 A 工作電源電壓:3.9 V to 17 V 最大工作溫度:+ 85 C 最小工作溫度:- 40 C 封裝 / 箱體:VQFN-24 封裝:Reel
MAX6783TEB+ 功能描述:電池管理 Quad 1%-Accurate Battery Monitor RoHS:否 制造商:Texas Instruments 電池類型:Li-Ion 輸出電壓:5 V 輸出電流:4.5 A 工作電源電壓:3.9 V to 17 V 最大工作溫度:+ 85 C 最小工作溫度:- 40 C 封裝 / 箱體:VQFN-24 封裝:Reel
MAX6783TEB+T 功能描述:電池管理 Quad 1%-Accurate Battery Monitor RoHS:否 制造商:Texas Instruments 電池類型:Li-Ion 輸出電壓:5 V 輸出電流:4.5 A 工作電源電壓:3.9 V to 17 V 最大工作溫度:+ 85 C 最小工作溫度:- 40 C 封裝 / 箱體:VQFN-24 封裝:Reel
MAX6783TEC+ 功能描述:電池管理 Quad 1%-Accurate Battery Monitor RoHS:否 制造商:Texas Instruments 電池類型:Li-Ion 輸出電壓:5 V 輸出電流:4.5 A 工作電源電壓:3.9 V to 17 V 最大工作溫度:+ 85 C 最小工作溫度:- 40 C 封裝 / 箱體:VQFN-24 封裝:Reel