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參數(shù)資料
| 型號： | L6611N |
| 廠商： | STMICROELECTRONICS |
| 元件分類： | 電源管理 |
| 英文描述： | 5-CHANNEL POWER SUPPLY SUPPORT CKT, PDIP20 |
| 封裝： | DIP-20 |
| 文件頁數(shù)： | 10/28頁 |
| 文件大?。?/td> | 662K |
| 代理商： | L6611N |
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L6611
18/28
2
ERROR AMPLIFIERS AND REFERENCE VOLTAGES
Three error amplifiers are implemented on the IC to achieve regulation of the output voltages: a brief description
follows for each section.
– Main section: error amplifier A and Soft-Start.
The circuit is designed to directly control the Main primary PWM through an optocoupler, providing
very good regulation and galvanic isolation from the primary side. Typical solutions require a shunt
regulator, like the TL431, as a reference and feedback amplifier to sense the output voltage and gen-
erate a corresponding error voltage; this voltage is then converted in a current transferred to the pri-
mary side through the optocoupler.
The feedback E/A amplifier is integrated in the IC: its non-inverting input is connected to an internally gen-
erated voltage reference, whose default value is typically 2.5V. It can however be trimmed to obtain a better
precision (see "On board trimming and mode operating" section). Then, no TL431 is needed.
The E/A inverting input (Ainv, pin#5) and the E/A output (Aout, pin#4) are externally available and the
frequency compensation network (Zc) will be connected between them (see fig. 15).
The high impedance (in the hundred k
) internal divider from 12V and 5V UV/OV sense pins elimi-
nates the need for an external one in most applications, allowing a further reduction in the number of
external component.
Under closed loop condition, the two upper branches, connected to 12V and 5V pins, supply equally
the current flowing through R3= 80.6K (equal to 2.5V/R3).
In order to avoid high current peaks in the primary circuit and output voltage overshoots at start-up,
the IC provides an on-board 8ms soft-start, a quasi-monotonic ramp from 0V to 2.5V for the A error
amplifier reference voltage,. In fact, if this reference gets the nominal value as soon as the power-up
occurs, the A E/A will go out of regulation and tend to sink much more current, thus forcing PWM to
work with the maximum duty-cycle.
– E/A and references voltage
Being the inverting input of E/A externally available, it is possible to change the "weight" of the two
contributions or even eliminate one of them by connecting external resistors of much lower value (RL,
RH1 and/or RH2 in fig. 15) that bypass the internal ones appropriately.
For example using RL=2.4K, RH1=3.9K and RH2=24K, then the ratio between +5V and +12V output
weight will be equal to 6:4.
By simply making RH1 = RL (for example 2.4K) with no RH2, only the +5V output is kept under feed-
back because the contribution of +12V branch (through the internal 600K resistor) will be negligible.
The pin #24 (12V) has to be connected to +12V output to guarantee the OV/UV monitoring.
Figure 15. Main feedback section
– 3.3V section, error amplifier B.
It is the error amplifier used to set the magamp core through an external circuitry (see a typical sche-
matic in figure 16).
The non-inverting input of the error amplifier is connected to a trimmable 1.25V internal voltage ref-
erence (see "On board trimming and mode operating" paragraph). The E/A inverting input is exter-
nally available (Binv, pin#2) and is connected to the output divider (RH and RL); the output pin (Bout,
V
DD
to MAIN
control
Zc
Aout
R
B
12V
5V
+2.5V
600K
168K
80.6K
8ms SS
L6611
GND
_
+
+12V output
+5V output
Ainv
R
L
R
H1
R
H2
optional, to change
feedback weight
V
DD
to MAIN
control
Zc
Aout
R
B
12V
5V
+2.5V
600K
168K
80.6K
8ms SS
L6611
GND
_
+
+12V output
+5V output
Ainv
R
L
R
H1
R
H2
optional, to change
feedback weight
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| L6712DTR | 2 A SWITCHING CONTROLLER, PDSO28 |
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相關代理商/技術參數(shù) |
參數(shù)描述 |
|---|---|
| L6615 | 制造商:STMICROELECTRONICS 制造商全稱:STMicroelectronics 功能描述:HIGH/LOW SIDE LOAD SHARE CONTROLLER |
| L6615D | 功能描述:DC/DC 開關控制器 H/L Load Share Cont RoHS:否 制造商:Texas Instruments 輸入電壓:6 V to 100 V 開關頻率: 輸出電壓:1.215 V to 80 V 輸出電流:3.5 A 輸出端數(shù)量:1 最大工作溫度:+ 125 C 安裝風格: 封裝 / 箱體:CPAK |
| L6615D013TR | 功能描述:DC/DC 開關控制器 H/L Load Share Cont RoHS:否 制造商:Texas Instruments 輸入電壓:6 V to 100 V 開關頻率: 輸出電壓:1.215 V to 80 V 輸出電流:3.5 A 輸出端數(shù)量:1 最大工作溫度:+ 125 C 安裝風格: 封裝 / 箱體:CPAK |
| L6615DTR | 制造商:STMICROELECTRONICS 制造商全稱:STMicroelectronics 功能描述:HIGH/LOW SIDE LOAD SHARE CONTROLLER |
| L6615N | 功能描述:DC/DC 開關控制器 H/L Load Share Cont RoHS:否 制造商:Texas Instruments 輸入電壓:6 V to 100 V 開關頻率: 輸出電壓:1.215 V to 80 V 輸出電流:3.5 A 輸出端數(shù)量:1 最大工作溫度:+ 125 C 安裝風格: 封裝 / 箱體:CPAK |
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