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參數(shù)資料
| 型號(hào)： | ADP3810AR-126 |
| 廠商： | Analog Devices, Inc. |
| 元件分類： | 圓形連接器 |
| 英文描述： | Top Entry Connector Hood; Enclosure Material:Aluminum Alloy; For Use With:C146 Rectangular Circular Connectors; Connecting Termination:Screw; Gender:Male; No. of Contacts:48; Operating Voltage:400V; Series:C-146 RoHS Compliant: Yes |
| 中文描述： | 二次側(cè)，離線電池充電器控制器 |
| 文件頁數(shù)： | 12/16頁 |
| 文件大?。?/td> | 457K |
| 代理商： | ADP3810AR-126 |
ADP3810/ADP3811
–12–
REV. 0
The trade-off between using a linear regulator as shown versus
using a flyback or buck type of charger is efficiency versus sim-
plicity. The linear charger in Figure 29 is very simple, and it
uses a minimal amount of external components. However, the
efficiency is poor, especially when there is a large delta between
the input output voltages. The power loss in the pass transistor
is equal to (V
IN
–V
BAT
)
×
I
CHARGE
. Since the circuit is powered
from a wall adapter, efficiency may not be a big concern, but the
heat dissipated in the pass transistor could be excessive.
An important specification for this circuit is the dropout voltage,
which is the difference between the input and output voltage at
full charge current. There must be enough voltage to keep the
N-channel MOSFET on. In this case, the dropout voltage is
approximately 2.2 V for a 0.5 A output current. Two alternative
IRF7205
V
IN
ADP3811
OUT
2N3904
V
BAT
10k
1k
ADP3811
V
REF
2N5058
V
IN
ADP3811
OUT
2N3904
V
BAT
10k
250
2N3904
1k
a. P-Channel MOSFET b. NPN Darlington
Figure 30. Alternative Pass Transistor for Linear Regulator
realizations of the pass element are shown in Figure 30. In case
(a), the pass transistor is a P-channel MOSFET. This provides
a lower dropout voltage so that V
BAT
can be within a few hun-
dred millivolts of V
IN
. In case (b), a Darlington configuration of
two npn transistors is used. The dropout voltage of this circuit
is approximately 2 V for a 0.5 A charge current.
STABILIZATION OF FEEDBACK LOOPS
The ADP3810/ADP3811 uses two transconductance error am-
plifiers with “merged” output stages to create a shared compen-
sation point (COMP) for both the current and voltage loops as
explained previously. Since the voltage and current loops have
significantly different natural crossover frequencies in a battery
charger application, the two loops need different inverted zero
feedback loop compensations that can be accomplished by two
series RC networks. One provides the needed low frequency
(typical f
C
< 100 Hz) compensation to the voltage loop, and the
other provides a separate high frequency (f
C
~ 1 kHz–10 kHz)
compensation to the current loop. In addition, the current loop
input requires a ripple reduction filter on the V
CS
pin to filter
out switching noise. Instead of placing both RC networks on the
COMP pin, the current loop network is placed between V
CS
and
ground as shown in Figure 23 (C
C2
and R
C2)
. Thus, it performs
two functions, ripple reduction and loop compensation.
Loop Stability Criteria for Battery Charger Applications
1. The voltage loop has to be stable when the battery is
removed or floating.
2. The current loop has to be stable when the battery is being
charged within its specified charge current range.
3. Both loops have to be stable within the specified input source
voltage range.
Flyback Charger Compensation
Figure 31 shows a simplified form of a battery charger system
based on the off-line flyback converter presented in Figure 23.
With some modifications (no optocoupler, for example), this
model can also be used for converters such as a Buck Converter
(Figure 28) or a Linear Regulator (Figure 29). GM1 and GM2
are the internal GM amplifiers of the ADP3810/ADP3811, and
GM3 is the buffered output stage that drives the optocoupler.
The primary side in Figure 23 is represented here by the “Power
Stage,” which is modeled as GM4, a linear voltage controlled
current source model of the flyback transformer and switch.
The “Voltage Error Amplifier” block is the internal error ampli-
fier of the 3845 PWM-IC (R
F
= 3.3 k
in Figure 23), and it is
followed by an internal resistor divider. The optocoupler is
modeled as a current controlled current source as shown. Its
output current develops a voltage, V
X
, across R
F
. The gain val-
ues of all the blocks are defined below.
This linear model makes the calculation of compensation values
a manageable task. It also has the great benefit of allowing the
simulation of the ac response using a circuit simulator, such
as PSpice or MicroCap. For computer modeling, the GM
0.25
*
IRF7201
20k
*
R
C1
200
C
C1
1μF
0.1μF
0.1μF
C
220nF
0.1μF
V
CC
V
SENSE
+V
IN
GND
V
CS
V
REF
V
CTRL
COMP
OUT
ADP3811
V
CTRL
V
CTRL
&
V
REF
RTN
R
C2
560
2N3904
V
BAT
10k
220μF
1k
BATTERY
1μF
V
REF
V
IN
RTN
R1
80.6k
R2
20k
R8
1k
250
V
BAT
= 2.0V
(
R2
)
Figure 29. ADP3811 Controlling a Linear Battery Charger
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| ADP3810AR-168 | Circular Connector Cable Assembly; Connector Type A:Circular Plug; Connector Type B:Stripped End Leads; Cable Length:10ft; Features:500 Mating Cycles, PVC Jacket, IP67 Rating, E63093 Rated Connector; No. of Contacts:3 RoHS Compliant: Yes |
| ADP3820AR-41 | Circular Connector Cable Assembly; Connector Type A:Circular Receptacle; Connector Type B:Stripped End Leads; Cable Length:10ft RoHS Compliant: Yes |
| ADP3820AR-42 | Circular Connector Cable Assembly; Connector Type A:Circular Receptacle; Connector Type B:Stripped End Leads; Cable Length:10ft RoHS Compliant: Yes |
| ADP3820ART-41 | Lithium-Ion Battery Charger |
| ADP3820ART-42 | Circular Connector; No. of Contacts:17; Series:; Body Material:Aluminum Alloy; Connecting Termination:Solder; Connector Shell Size:20; Circular Contact Gender:Socket; Circular Shell Style:Cable Receptacle; Insert Arrangement:20-29 RoHS Compliant: No |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| ADP3810AR-16.8 | 制造商:Analog Devices 功能描述:Battery Charger 6mA 16.8V 8-Pin SOIC N 制造商:Rochester Electronics LLC 功能描述:- Bulk |
| ADP3810AR-168 | 制造商:AD 制造商全稱:Analog Devices 功能描述:Secondary Side, Off-Line Battery Charger Controllers |
| ADP3810AR-4.2 | 制造商:Rochester Electronics LLC 功能描述:OFF-LINE BATTERY CHARGER CONTROLLER-4.2V - Bulk 制造商:Analog Devices 功能描述: |
| ADP3810AR-42 | 制造商:AD 制造商全稱:Analog Devices 功能描述:Secondary Side, Off-Line Battery Charger Controllers |
| ADP3810AR-8.4 | 制造商:Analog Devices 功能描述:Battery Charger 6mA 8.4V 8-Pin SOIC N 制造商:Rochester Electronics LLC 功能描述:- Bulk |
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