參數(shù)資料
型號: L6599ATDTR
廠商: STMICROELECTRONICS
元件分類: 穩(wěn)壓器
英文描述: SWITCHING CONTROLLER, 500 kHz SWITCHING FREQ-MAX, PDSO16
封裝: SOP-16
文件頁數(shù): 7/31頁
文件大?。?/td> 861K
代理商: L6599ATDTR
L6599AT
Application information
Doc ID 15534 Rev 3
15/31
Figure 6.
Oscillator waveforms and their relationship with gate-driving signals
In Figure 6 the timing relationship between the oscillator waveform and the gate-drive
signal, as well as the swinging node of the half-bridge leg (HB) is shown. Note that the low-
side gate-drive is turned on while the oscillator's triangle is ramping up and the high-side
gate-drive is turned on while the triangle is ramping down. In this way, at start-up, or as the
IC resumes switching during burst-mode operation, the low-side MOSFET is switched on
first to charge the bootstrap capacitor. As a result, the bootstrap capacitor is always charged
and ready to supply the high-side floating driver.
6.2
Operation at no load or very light load
When the resonant half-bridge is lightly loaded or not loaded at all, its switching frequency is
at its maximum value. To keep the output voltage under control in these conditions and to
avoid losing soft-switching, there must be some significant residual current flowing through
the transformer's magnetizing inductance. This current, however, produces some
associated losses that prevent converter's no-load consumption from achieving very low
values.
To overcome this issue, the L6599AT enables the designer to make the converter operate
intermittently (burst-mode operation), with a series of a few switching cycles spaced out by
long idle periods where both MOSFETs are in OFF-state, so that the average switching
frequency can be substantially reduced. As a result, the average value of the residual
magnetizing current and the associated losses is considerably cut down, thus facilitating the
converter to comply with energy saving recommendations.
The L6599AT can be operated in burst-mode by using pin 5 (STBY): if the voltage applied to
this pin falls below 1.24 V the IC enters an idle state where both gate-drive outputs are low,
the oscillator is stopped, the soft-start capacitor CSS keeps its charge and only the 2 V
reference at RFmin pin stays alive to minimize the IC's consumption and the VCC capacitor's
discharge. The IC resumes normal operation as the voltage on the pin exceeds 1.24 V by 50
mV.
To implement burst-mode operation the voltage applied to the STBY pin needs to be related
to the feedback loop. Figure 7a shows the simplest implementation, suitable for a narrow
input voltage range (e.g. when there is a PFC front-end).
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相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
L6599ATN 制造商:STMicroelectronics 功能描述:
L6599D 功能描述:軟開關(guān) PWM 控制器 Hi Vltg resonant Controller RoHS:否 制造商:Fairchild Semiconductor 輸出端數(shù)量: 輸出電流: 開關(guān)頻率: 工作電源電壓:30 V 電源電流: 最大工作溫度:+ 105 C 最小工作溫度:- 40 C 安裝風格:SMD/SMT 封裝 / 箱體:SOIC-8 封裝:Reel
L6599DTR 功能描述:軟開關(guān) PWM 控制器 Hi Vltg resonant Controller RoHS:否 制造商:Fairchild Semiconductor 輸出端數(shù)量: 輸出電流: 開關(guān)頻率: 工作電源電壓:30 V 電源電流: 最大工作溫度:+ 105 C 最小工作溫度:- 40 C 安裝風格:SMD/SMT 封裝 / 箱體:SOIC-8 封裝:Reel
L6599N 功能描述:軟開關(guān) PWM 控制器 Hi Vltg resonant Controller RoHS:否 制造商:Fairchild Semiconductor 輸出端數(shù)量: 輸出電流: 開關(guān)頻率: 工作電源電壓:30 V 電源電流: 最大工作溫度:+ 105 C 最小工作溫度:- 40 C 安裝風格:SMD/SMT 封裝 / 箱體:SOIC-8 封裝:Reel
L6599NR 功能描述:電壓模式 PWM 控制器 HV resonant CNTRL RoHS:否 制造商:Texas Instruments 輸出端數(shù)量:1 拓撲結(jié)構(gòu):Buck 輸出電壓:34 V 輸出電流: 開關(guān)頻率: 工作電源電壓:4.5 V to 5.5 V 電源電流:600 uA 最大工作溫度:+ 125 C 最小工作溫度:- 40 C 封裝 / 箱體:WSON-8 封裝:Reel