- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄383182 > ISL9440A (Intersil Corporation) Triple, 180∑ Out-of-Phase, Step-Down PWM and Single Linear Controller PDF資料下載
參數(shù)資料
| 型號： | ISL9440A |
| 廠商： | Intersil Corporation |
| 英文描述： | Triple, 180∑ Out-of-Phase, Step-Down PWM and Single Linear Controller |
| 中文描述： | 三，180Σ門診的階段，降壓型PWM和線性控制器單 |
| 文件頁數(shù)： | 16/20頁 |
| 文件大?。?/td> | 978K |
| 代理商： | ISL9440A |
16
FN6383.1
December 5, 2007
Figure 17 shows a Type 2 amplifier and its response along
with the responses of the current mode modulator and the
converter. The Type 2 amplifier, in addition to the pole at
origin, has a zero-pole pair that causes a flat gain region at
frequencies in between the zero and the pole.
The zero frequency, the amplifier high-frequency gain, and
the modulator gain are chosen to satisfy most typical
applications. The crossover frequency will appear at the
point where the modulator attenuation equals the amplifier
high frequency gain. The only task that the system designer
has to complete is to specify the output filter capacitors to
position the load main pole somewhere within one decade
lower than the amplifier zero frequency. With this type of
compensation plenty of phase margin is easily achieved due
to zero-pole pair phase ‘boost’.
Conditional stability may occur only when the main load pole
is positioned too much to the left side on the frequency axis
due to excessive output filter capacitance. In this case, the
ESR zero placed within the 1.2kHz to 30kHz range gives
some additional phase ‘boost’. Some phase boost can also
be achieved by connecting capacitor C
Z
in parallel with the
upper resistor R
1
of the divider that sets the output voltage
value. Please refer to “Output Inductor Selection” on
page 18 and “Input Capacitor Selection” on page 19 for
further details.
Linear Regulator
The linear regulator controller is a trans-conductance
amplifier with a nominal gain of 2A/V. The N-channel
MOSFET output device can sink a minimum of 50mA. The
reference voltage is 0.8V. With zero volts differential at it’s
input, the controller sinks 21mA of current. An external PNP
transistor or PFET pass element can be used. The dominant
pole for the loop can be placed at the base of the PNP (or
gate of the PFET), as a capacitor from emitter to base
(source to gate of a PFET). Better load transient response is
achieved however, if the dominant pole is placed at the
output, with a capacitor to ground at the output of the
regulator.
Under no-load conditions, leakage currents from the pass
transistors supply the output capacitors, even when the
transistor is off. Generally this is not a problem since the
feedback resistor drains the excess charge. However,
charge may build up on the output capacitor making V
LDO
rise above its set point. Care must be taken to insure that the
feedback resistor’s current exceeds the pass transistors
leakage current over the entire temperature range.
The linear regulator output can be supplied by the output of
one of the PWMs. When using a PFET, the output of the
linear regulator will track the PWM supply after the PWM
output rises to a voltage greater than the threshold of the
PFET pass device. The voltage differential between the
PWM and the linear output will be the load current times the
r
DS(ON)
.
Base-Drive Noise Reduction
The high-impedance base driver is susceptible to system
noise, especially when the linear regulator is lightly loaded.
Capacitively coupled switching noise or inductively coupled
EMI onto the base drive causes fluctuations in the base
current, which appear as noise on the linear regulator’s
output. Keep the base drive traces away from the step-down
converter, and as short as possible, to minimize noise
coupling. A resistor in series with the gate drivers reduces
the switching noise generated by PWM. Additionally, a
bypass capacitor may be placed across the base-to-emitter
resistor. This bypass capacitor, in addition to the transistor’s
input capacitor, could bring in a second pole that will de-
stabilize the linear regulator. Therefore, the stability
F
Z
2
1
------------------------------
6kHz
=
=
(EQ. 8)
F
P
2
π
R
1
C
2
------------------------------
600kHz
=
=
(EQ. 9)
FIGURE 17. FEEDBACK LOOP COMPENSATION
R1
R2
C1
C2
F
PO
F
Z
F
P
F
C
MODULATOR
EA
CONVERTER
TYPE 2 EA
G
EA
= 18dB
G
M
= 17.5dB
0.79
0.8
0.82
0.83
0.85
0
40
60
FEEDBACK VOLTAGE (V)
E
20
50
30
10
C
0.81
0.84
FIGURE 18. LINEAR CONTROLLER GAIN
ISL9440, ISL9440A, ISL9441
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| ISL9441 | Triple, 180∑ Out-of-Phase, Step-Down PWM and Single Linear Controller |
| ISL95810UIRT8 | Low Noise, Low Power I2C Bus, 256 Taps |
| ISL95810UIU8Z | Single Digitally Controlled Potentiometer (XDCP) |
| ISL95810 | Single Digitally Controlled Potentiometer (XDCP) |
| ISL95810WIU8Z | Single Digitally Controlled Potentiometer (XDCP) |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| ISL9440AEVAL1Z | 功能描述:EVALUATION BOARD FOR ISL9440 RoHS:是 類別:編程器，開發(fā)系統(tǒng) >> 評估板 - DC/DC 與 AC/DC（離線）SMPS 系列:- 產(chǎn)品培訓(xùn)模塊:Obsolescence Mitigation Program 標準包裝:1 系列:True Shutdown™ 主要目的:DC/DC，步升 輸出及類型:1，非隔離 功率 - 輸出:- 輸出電壓:- 電流 - 輸出:1A 輸入電壓:2.5 V ~ 5.5 V 穩(wěn)壓器拓撲結(jié)構(gòu):升壓 頻率 - 開關(guān):3MHz 板類型:完全填充 已供物品:板 已用 IC / 零件:MAX8969 |
| ISL9440AIRZ | 功能描述:IC REG QD BCK/LINEAR SYNC 32-QFN RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - 線性 + 切換式 系列:- 標準包裝:2,500 系列:- 拓撲:降壓（降壓）同步（3），線性（LDO）（2） 功能:任何功能 輸出數(shù):5 頻率 - 開關(guān):300kHz 電壓/電流 - 輸出 1:控制器 電壓/電流 - 輸出 2:控制器 電壓/電流 - 輸出 3:控制器 帶 LED 驅(qū)動器:無 帶監(jiān)控器:無 帶序列發(fā)生器:是 電源電壓:5.6 V ~ 24 V 工作溫度:-40°C ~ 85°C 安裝類型:* 封裝/外殼:* 供應(yīng)商設(shè)備封裝:* 包裝:* |
| ISL9440AIRZ-T | 功能描述:IC REG QD BCK/LINEAR SYNC 32-QFN RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - 線性 + 切換式 系列:- 標準包裝:2,500 系列:- 拓撲:降壓（降壓）同步（2），線性（LDO）（1） 功能:任何功能 輸出數(shù):3 頻率 - 開關(guān):300kHz 電壓/電流 - 輸出 1:控制器 電壓/電流 - 輸出 2:控制器 電壓/電流 - 輸出 3:控制器 帶 LED 驅(qū)動器:無 帶監(jiān)控器:無 帶序列發(fā)生器:是 電源電壓:4.5 V ~ 24 V 工作溫度:-40°C ~ 85°C 安裝類型:* 封裝/外殼:28-TSSOP（0.173"，4.40mm 寬） 供應(yīng)商設(shè)備封裝:* 包裝:帶卷 (TR) 其它名稱:ISL6402IVZ-TTR |
| ISL9440BEVAL1Z | 功能描述:EVAL BOARD 1 FOR ISL9440B RoHS:是 類別:編程器，開發(fā)系統(tǒng) >> 評估板 - DC/DC 與 AC/DC（離線）SMPS 系列:* 產(chǎn)品培訓(xùn)模塊:Obsolescence Mitigation Program 標準包裝:1 系列:True Shutdown™ 主要目的:DC/DC，步升 輸出及類型:1，非隔離 功率 - 輸出:- 輸出電壓:- 電流 - 輸出:1A 輸入電壓:2.5 V ~ 5.5 V 穩(wěn)壓器拓撲結(jié)構(gòu):升壓 頻率 - 開關(guān):3MHz 板類型:完全填充 已供物品:板 已用 IC / 零件:MAX8969 |
| ISL9440BIRZ | 功能描述:IC REG QD BCK/LINEAR SYNC 32-QFN RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - 線性 + 切換式 系列:- 標準包裝:2,500 系列:- 拓撲:降壓（降壓）同步（2），線性（LDO）（1） 功能:任何功能 輸出數(shù):3 頻率 - 開關(guān):300kHz 電壓/電流 - 輸出 1:控制器 電壓/電流 - 輸出 2:控制器 電壓/電流 - 輸出 3:控制器 帶 LED 驅(qū)動器:無 帶監(jiān)控器:無 帶序列發(fā)生器:是 電源電壓:4.5 V ~ 24 V 工作溫度:-40°C ~ 85°C 安裝類型:* 封裝/外殼:28-TSSOP（0.173"，4.40mm 寬） 供應(yīng)商設(shè)備封裝:* 包裝:帶卷 (TR) 其它名稱:ISL6402IVZ-TTR |
發(fā)布緊急采購，3分鐘左右您將得到回復(fù)。