參數(shù)資料
型號(hào): ISL6219ACA
廠商: INTERSIL CORP
元件分類: 穩(wěn)壓器
英文描述: Microprocessor CORE Voltage Regulator Precision Multi-Phase BUCK PWM Controller for Mobile Applications
中文描述: SWITCHING CONTROLLER, 1500 kHz SWITCHING FREQ-MAX, PDSO28
封裝: 0.150 INCH, PLASTIC, QSOP-28
文件頁數(shù): 8/17頁
文件大小: 408K
代理商: ISL6219ACA
8
must use an input capacitor bank with twice the rms current
capacity as the equivalent three-phase converter.
Figures 14 and 15 in the section entitled
Input Capacitor
Selection
can be used to determine the input-capacitor rms
current based on load current, duty cycle, and the number of
active channels. They are provided as aids in determining
the optimal input capacitor solution. Figure 16 shows the
single phase input-capacitor rms current for comparisson.
PWM OPERATION
The number of active channels selected determines the
timing for each channel. By default, the timing mode for the
ISL6219A is 3-phase. The designer can select 2-phase
timing by connecting PWM3 to VCC.
One switching cycle for the ISL6219A is defined as the time
between PWM1 pulse termination signals (the internal signal
that initiates a falling edge on PWM1). The cycle time is the
inverse of the switching frequency selected by the resistor
connected between the FS/EN pin and ground (see
Switching Frequency
). Each cycle begins when a clock
signal commands the channel-1 PWM output to go low. This
signals the channel-1 MOSFET driver to turn off the
channel-1 upper MOSFET and turn on the channel-1
synchronous MOSFET. If two-channel operation is selected,
the PWM2 pulse terminates 1/2 of a cycle later. If three
channels are selected the PWM2 pulse terminates 1/3 of a
cycle after PWM1, and the PWM3 output will follow after
another 1/3 of a cycle.
Once a channel’s PWM pulse terminates, it remains low for
a minimum of 1/4 cycle. This forced off time is required to
assure an accurate current sample as described in
Current
Sensing
. Following the 1/4-cycle forced off time, the
controller enables the PWM output. Once enabled, the PWM
output transitions high when the sawtooth signal crosses the
adjusted error-amplifier output signal, V
COMP
as illustrated
in Figures 1 and 5. This is the signal for the MOSFET driver
to turn off the synchronous MOSFET and turn on the upper
MOSFET. The output will remain high until the clock signals
the beginning of the next cycle by commanding the PWM
pulse to terminate.
CURRENT SENSING
Intersil multi-phase controllers sense current by sampling the
voltage across the lower MOSFET during its conduction
interval. MOSFET r
DS(ON)
sensing is a no-added-cost
method to sense current for load-line regulation, channel-
current balance, module current sharing, and overcurrent
protection. If desired, an independent current-sense resistor
in series with the lower-MOSFET source can serve as a
sense element in place of the MOSFET r
DS(ON).
The ISEN input for each channel uses a ground-referenced
amplifier to reproduce a signal proportional to the channel
current (Figure 4). After sufficient settling time, the sensed
current is sampled, and the sample is used for current
balance, load-line regulation and overcurrent protection. The
ISL6219A samples channel current once each cycle. Figure
4 shows how the sampled current, I
n
, is created from the
channel current I
L
. The circuitry in Figure 4 represents the
current measurement and sampling circuitry for channel n in
an N-channel converter. This circuitry is repeated for each
channel in the converter but will not be active in unused
channels
.
CHANNEL-CURRENT BALANCE
Another benefit of multi-phase operation is the thermal
advantage gained by distributing the dissipated heat over
multiple devices and greater area. By doing this, the
designer avoids the complexity of driving multiple parallel
MOSFETs and the expense of using expensive heat sinks
and exotic magnetic materials.
In order to fully realize the thermal advantage, it is important
that each channel in a multi-phase converter be controlled to
deliver about the same current at any load level. Intersil
multi-phase controllers guarantee current balance by
comparing each channel’s current to the average current
delivered by all channels and making an appropriate
adjustment to each channel’s pulse width based on the
error. Intersil’s patented current-balance method is
illustrated in Figure 5 where the average of the 2 or 3
sampled channel currents combines with the channel 1
sample, I
1
, to create an error signal I
ER
. The filtered error
signal modifies the pulse width commanded by V
COMP
to
correct any unbalance and force I
ER
toward zero.
In some circumstances, it may be necessary to deliberately
design some channel-current unbalance into the system. In
a highly compact design, one or two channels may be able
FIGURE 4. INTERNAL AND EXTERNAL CURRENT-SENSING
CIRCUITRY
I
n
ISEN
IL
)
-------------------------
=
-
+
ISEN(n)
R
ISEN
SAMPLE
&
HOLD
ISL6219A INTERNAL CIRCUIT
EXTERNAL CIRCUIT
V
IN
CHANNEL N
UPPER MOSFET
CHANNEL N
LOWER MOSFET
-
+
ILrDS ON
(
)
I
L
ISL6219A
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相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
ISL6219ACA-T 功能描述:IC REG CTRLR BUCK PWM VM 28-SSOP RoHS:否 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 切換控制器 系列:- 標(biāo)準(zhǔn)包裝:4,000 系列:- PWM 型:電壓模式 輸出數(shù):1 頻率 - 最大:1.5MHz 占空比:66.7% 電源電壓:4.75 V ~ 5.25 V 降壓:是 升壓:無 回掃:無 反相:無 倍增器:無 除法器:無 Cuk:無 隔離:無 工作溫度:-40°C ~ 85°C 封裝/外殼:40-VFQFN 裸露焊盤 包裝:帶卷 (TR)
ISL6219ACAZ 功能描述:IC REG CTRLR BUCK PWM VM 28-QSOP RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 切換控制器 系列:- 標(biāo)準(zhǔn)包裝:2,500 系列:- PWM 型:電流模式 輸出數(shù):1 頻率 - 最大:500kHz 占空比:100% 電源電壓:8.2 V ~ 30 V 降壓:無 升壓:無 回掃:是 反相:無 倍增器:無 除法器:無 Cuk:無 隔離:是 工作溫度:0°C ~ 70°C 封裝/外殼:8-DIP(0.300",7.62mm) 包裝:管件 產(chǎn)品目錄頁面:1316 (CN2011-ZH PDF)
ISL6219ACAZ-T 功能描述:IC REG CTRLR BUCK PWM VM 28-QSOP RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 切換控制器 系列:- 標(biāo)準(zhǔn)包裝:2,500 系列:- PWM 型:電流模式 輸出數(shù):1 頻率 - 最大:500kHz 占空比:100% 電源電壓:8.2 V ~ 30 V 降壓:無 升壓:無 回掃:是 反相:無 倍增器:無 除法器:無 Cuk:無 隔離:是 工作溫度:0°C ~ 70°C 封裝/外殼:8-DIP(0.300",7.62mm) 包裝:管件 產(chǎn)品目錄頁面:1316 (CN2011-ZH PDF)
ISL6219CA 制造商:Rochester Electronics LLC 功能描述:- Bulk
ISL6219CA-T 制造商:Rochester Electronics LLC 功能描述: 制造商:Intersil Corporation 功能描述: