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參數(shù)資料
| 型號(hào)： | ISL97652IRZ-TK |
| 廠商： | INTERSIL CORP |
| 元件分類： | 穩(wěn)壓器 |
| 英文描述： | 4-Channel Integrated LCD Supply with Dual VCOM Amplifiers |
| 中文描述： | 2.5 A SWITCHING REGULATOR, 1500 kHz SWITCHING FREQ-MAX, PQCC48 |
| 封裝： | 7 X 7 MM, ROHS COMPLIANT, PLASTIC, MO-220VKKD-2, QFN-48 |
| 文件頁數(shù)： | 12/25頁 |
| 文件大?。?/td> | 709K |
| 代理商： | ISL97652IRZ-TK |
12
FN9287.0
December 21, 2006
The boost converter uses a summing amplifier architecture
consisting of gm stages for voltage feedback, current
feedback and slope compensation. A comparator looks at
the peak inductor current cycle by cycle and terminates the
PWM cycle if the current limit is reached.
An external resistor divider is required to divide the output
voltage down to the nominal reference voltage. Current
drawn by the resistor network should be limited to maintain
the overall converter efficiency. The maximum value of the
resistor network is limited by the feedback input bias current
and the potential for noise being coupled into the feedback
pin. A resistor network in the order of 60k
Ω
is recommended.
The boost converter output voltage is determined by the
following equation:
The current through the MOSFET is limited to 2.8Apeak.
This restricts the maximum output current (average) based
on the following equation:
Where
Δ
IL is peak to peak inductor ripple current, and is set by:
where f
s
is the switching frequency
The following table gives typical values (margins are
considered 10%, 3%, 20%, 10% and 15% on V
IN
, V
O
, L, f
S
and I
OMAX
):
When operating at the lower frequency option, 650kHz, the
potential increase in ripple current in the inductor can be
avoided by increasing the inductor by the same factor. This
allows the slope compensation in the boost feedback to
remain the same as the 1.3MHz case and this will maintain
stability of the converter over the widest operating range.
Operation at 650kHz allows boost operation down to lower
minimum duty cycles, where the output voltage required is
closer to the input voltage than can be achieved when the
higher frequency option is selected. The minimum boost
duty cycle of the ISL97652 is ~10% for 650kHz and ~20%
for 1.3MHz. When the operating duty cycle is lower than the
minimum duty cycle, the part will not switch in some cycles
randomly, which will cause some LX pulses to be skipped. In
this cas, LX pulses are not consistent any more, but the
output voltage (A
VDD
) is still regulated by the ratio of R1 and
R2. Because some LX pulses are skipped, the ripple current
in the inductor will become bigger. Under the worst case, the
ripple current will be from 0 to the threshold of the current
limit. In turn, the bigger ripple current will increase the output
voltage ripple. Hence, it will need more output capacitors to
keep the output ripple at the same level. When the input
voltage equals, or is larger than, the output voltage, the
boost converter will stop switching. The boost converter is
not regulated any more, but the part will still be on and other
channels are still regulated.
Boost Converter Input Capacitor
An input capacitor is used to suppress the voltage ripple
injected into the boost converter. A ceramic capacitor with
capacitance larger than 10μF is recommended. The voltage
rating of input capacitor should be larger than the maximum
input voltage. Some capacitors are recommended in Table 2
for input capacitor.
Boost Inductor
The boost inductor is a critical part which influences the
output voltage ripple, transient response, and efficiency.
Values of 3.3μH to 10μH should be selected to match the
internal slope compensation. The inductor must be able to
handle the following average and peak current:
Some inductors are recommended in Table 3.
TABLE 1. MAXIMUM OUTPUT CURRENT CALCULATION
V
IN
(V)
V
O
(V)
L (μH)
f
s
(MHz)
I
OMAX
(mA)
12
15
6.8
0.65
1890
12
15
6.8
1.3
1955
12
18
6.8
0.65
1500
12
18
6.8
1.3
1590
8
15
6.8
0.65
1200
8
15
6.8
1.3
1275
8
18
6.8
0.65
950
8
18
6.8
1.3
1050
V
BOOST
R
--------------------
R
2
+
2
V
FB
×
=
(EQ. 2)
I
OMAX
I
LMT
Δ
I
L
2
--------
–
V
O
---------
×
=
(EQ. 3)
Δ
I
L
V
---------
D
f
S
----
×
=
(EQ. 4)
TABLE 2. BOOST CONVERTER INPUT CAPACITOR
RECOMMENDATION
CAPACITOR
SIZE
VENDOR
PART NUMBER
10μF/25V
1210
TDK
C3225X7R1E106M
10μF/25V
1210
Murata
GRM32DR61E106K
TABLE 3. BOOST INDUCTOR RECOMMENDATION
INDUCTOR
DIMENSIONS
(mm)
VENDOR
PART NUMBER
6.8μH/
3A
PEAK
7.3x6.8x3.2
TDK
RLF7030T-6R8N3R0
6.8μH/
2.9A
PEAK
7.6X7.6X3.0
Sumida
CDR7D28MNNP-6R8NC
5.2μH/
4.55A
PEAK
10x10.1x3.8
Cooper
Bussmann
CD1-5R2
I
LAVG
I
D
---–
=
(EQ. 5)
I
LPK
I
LAVG
Δ
I
L
2
--------
+
=
(EQ. 6)
ISL97652
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| ISL97653A | 5-Channel Integrated LCD Supply |
| ISL97653AIRZ | 5-Channel Integrated LCD Supply |
| ISL97653AIRZ-T | 5-Channel Integrated LCD Supply |
| ISL97653AIRZ-TK | 5-Channel Integrated LCD Supply |
| ISL97702 | Boost with Dual Reference Outputs |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| ISL97653AIRZ | 功能描述:電流型 PWM 控制器 5-CH INTEGRTD LCD SUPPLY W/TEMP SENSOR RoHS:否 制造商:Texas Instruments 開關(guān)頻率:27 KHz 上升時(shí)間: 下降時(shí)間: 工作電源電壓:6 V to 15 V 工作電源電流:1.5 mA 輸出端數(shù)量:1 最大工作溫度:+ 105 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:TSSOP-14 |
| ISL97653AIRZ-T | 功能描述:電流型 PWM 控制器 5-CH INTEGRTD LCD SUPPLY W/TEMP SENSOR RoHS:否 制造商:Texas Instruments 開關(guān)頻率:27 KHz 上升時(shí)間: 下降時(shí)間: 工作電源電壓:6 V to 15 V 工作電源電流:1.5 mA 輸出端數(shù)量:1 最大工作溫度:+ 105 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:TSSOP-14 |
| ISL97653AIRZ-TK | 功能描述:電流型 PWM 控制器 5-CH INTEGRTD LCD SUPPLY W/TEMP SENSOR RoHS:否 制造商:Texas Instruments 開關(guān)頻率:27 KHz 上升時(shí)間: 下降時(shí)間: 工作電源電壓:6 V to 15 V 工作電源電流:1.5 mA 輸出端數(shù)量:1 最大工作溫度:+ 105 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:TSSOP-14 |
| ISL97653IRZ | 制造商:Intersil Corporation 功能描述: |
| ISL97656IRTZ | 功能描述:IC REG BOOST ADJ 4A 10TDFN RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 開關(guān)穩(wěn)壓器 系列:- 產(chǎn)品培訓(xùn)模塊:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 標(biāo)準(zhǔn)包裝:2,500 系列:- 類型:降壓（降壓） 輸出類型:兩者兼有 輸出數(shù):1 輸出電壓:5V，1 V ~ 10 V 輸入電壓:3.5 V ~ 28 V PWM 型:電流模式 頻率 - 開關(guān):220kHz ~ 1MHz 電流 - 輸出:600mA 同步整流器:無 工作溫度:-40°C ~ 125°C 安裝類型:表面貼裝 封裝/外殼:16-SSOP（0.154"，3.90mm 寬） 包裝:帶卷 (TR) 供應(yīng)商設(shè)備封裝:16-QSOP |
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