參數(shù)資料
型號: ISL6752
廠商: Intersil Corporation
英文描述: Octal Buffers/Drivers With 3-State Outputs 20-PDIP -40 to 85
中文描述: ZVS全橋電流模式PWM可調(diào)的同步整流控制
文件頁數(shù): 9/16頁
文件大?。?/td> 436K
代理商: ISL6752
9
FN9181.1
March 10, 2005
Voltages below 2.425V result in OUTLLN/OUTLRN being
advanced relative to OUTLL/OUTLR. Voltages above
2.575V result in OUTLLN/OUTLRN being delayed relative to
OUTLL/OUTLR. A voltage of 2.50 V ±75mV results in zero
phase difference. A weak internal 50% divider from VREF
results in no phase delay if this input is left floating.
The range of phase delay/advance is either zero or 40 to
300ns with the phase differential increasing as the voltage
deviation from 2.5V increases. The relationship between the
control voltage and phase differential is non-linear. The gain
(
t/
V) is low for control voltages near 2.5V and rapidly
increases as the voltage approaches the extremes of the
control range. This behavior provides the user increased
accuracy when selecting a shorter delay/advance duration.
VERR -
The control voltage input to the inverting input of the
PWM comparator. The output of an external error amplifier
(EA) is applied to this input, either directly or through an
opto-coupler, for closed loop regulation. VERR has a
nominal 1mA pull-up current source.
CTBUF -
CTBUF is the buffered output of the sawtooth
oscillator waveform present on CT and is capable of
sourcing 2mA. It is offset from ground by 0.40V and has a
nominal valley-to-peak gain of 2. It may be used for slope
compensation.
Functional Description
Features
The ISL6752 PWM is an excellent choice for low cost ZVS
full-bridge applications requiring adjustable synchronous
rectifier drive. With its many protection and control features,
a highly flexible design with minimal external components is
possible. Among its many features are a very accurate
overcurrent limit threshold, thermal protection, a buffered
sawtooth oscillator output suitable for slope compensation,
synchronous rectifier outputs with variable delay/advance
timing, and adjustable frequency.
If synchronous rectification is not required, please consider
the ISL6753 controller.
Oscillator
The ISL6752 has an oscillator with a programmable
frequency range to 2MHz, which can be programmed with a
resistor and capacitor.
The switching period is the sum of the timing capacitor
charge and discharge durations. The charge duration is
determined by CT and a fixed 200μA internal current source.
The discharge duration is determined by RTD and CT.
where T
C
and T
D
are the charge and discharge times,
respectively, CT is the timing capacitor in Farads, RTD is the
discharge programming resistance in ohms, T
SW
is the
oscillator period, and F
SW
is the oscillator frequency. One
output switching cycle requires two oscillator cycles. The
actual times will be slightly longer than calculated due to
internal propagation delays of approximately 10ns/transition.
This delay adds directly to the switching duration, but also
causes overshoot of the timing capacitor peak and valley
voltage thresholds, effectively increasing the peak-to-peak
voltage on the timing capacitor. Additionally, if very small
discharge currents are used, there will be increased error
due to the input impedance at the CT pin. The maximum
recommended current through RTD is 1mA, which produces
a CT discharge current of 20mA.
The maximum duty cycle, D, and percent deadtime, DT, can
be calculated from:
Implementing Soft-Start
The ISL6752 does not have a soft-start feature. Soft-start
can be implemented externally using the components shown
below. The RC network governs the rate of rise of the
transistor’s base which clamps the voltage at VERR.
T
C
11.5 10
3
CT
S
(EQ. 1)
T
D
0.06 RTD CT
(
)
50 10
9
+
S
(EQ. 2)
T
SW
T
C
T
D
+
SW
------------
=
=
S
(EQ. 3)
D
T
SW
------------
=
(EQ. 4)
DT
1
D
=
(EQ. 5)
ISL6752
相關(guān)PDF資料
PDF描述
ISL6752AAZA-T ZVS Full-Bridge Current-Mode PWM with Adjustable Synchronous Rectifier Control
ISL6752AAZA Octal Buffers/Drivers With 3-State Outputs 20-PDIP -40 to 85
ISL6753 Octal Buffers/Drivers With 3-State Outputs 20-SO -40 to 85
ISL6753AAZA-T ZVS Full-Bridge PWM Controller
ISL6753AAZA Octal Buffers/Drivers With 3-State Outputs 20-SO -40 to 85
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
ISL6752/54EVAL1Z 功能描述:BOARD DEMO FOR ISL6752 ISL6754 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(biāo)準(zhǔn)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?fù)浣Y(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
ISL6752AAZA 功能描述:IC REG CTRLR PWM CM 16-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:75 系列:- PWM 型:電流模式 輸出數(shù):1 頻率 - 最大:1MHz 占空比:81% 電源電壓:4.3 V ~ 13.5 V 降壓:是 升壓:是 回掃:是 反相:無 倍增器:無 除法器:無 Cuk:無 隔離:無 工作溫度:0°C ~ 70°C 封裝/外殼:8-SOIC(0.154",3.90mm 寬) 包裝:管件 產(chǎn)品目錄頁面:1051 (CN2011-ZH PDF) 其它名稱:296-2543-5
ISL6752AAZAR5325 制造商:Intersil Corporation 功能描述:- Rail/Tube
ISL6752AAZA-T 功能描述:IC REG CTRLR PWM CM 16-QSOP RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 切換控制器 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:- PWM 型:電流模式 輸出數(shù):1 頻率 - 最大:275kHz 占空比:50% 電源電壓:18 V ~ 110 V 降壓:無 升壓:無 回掃:無 反相:無 倍增器:無 除法器:無 Cuk:無 隔離:是 工作溫度:-40°C ~ 85°C 封裝/外殼:8-SOIC(0.154",3.90mm 寬) 包裝:帶卷 (TR)
ISL6752AAZA-TR5325 制造商:Intersil Corporation 功能描述:ZVS Full-Bridge Current-Mode PWM with Adjustable Synchronous Rectifier Control