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參數(shù)資料
| 型號(hào)： | IR2520 |
| 廠商： | International Rectifier |
| 英文描述： | ADAPTIVE BALLAST CONTROL IC |
| 中文描述： | 自適應(yīng)鎮(zhèn)流器控制IC |
| 文件頁數(shù)： | 10/17頁 |
| 文件大小： | 335K |
| 代理商： | IR2520 |
IR2520D(S)& (PbF)
10
www.irf.com
over-current fault. By using the RDSon of the external low-
side MOSFET for current sensing and the VS-sensing
circuitry, the IR2520D eliminates the need for an additional
current sensing resistor, filter and current-sensing pin. To
cancel changes in the RDSon value due to temperature and
MOSFET variations, the IR2520D performs a crest factor
measurement that detects when the peak current exceeds
the average current by a factor of 5 (CSCF). Measuring the
crest factor is ideal for detecting when the inductor saturates
due to excessive current that occurs in the resonant tank
when the frequency sweeps through resonance and the
lamp does not ignite. When the VCO voltage ramps up for
the first time from zero, the resonant tank current and
voltages increase as the frequency decreases towards
resonance (Figure 8). If the lamp does not ignite, the inductor
current will eventually saturate but the crest factor fault
protection is not active until the VCO voltage exceeds 4.8V
(V
VCO_RUN
) for the first time. The frequency will continue
decreasing to the capacitive side of resonance towards
the minimum frequency setting and the resonant tank current
and voltages will decrease again. When the VCO voltage
exceeds 4.8V (V
VCO_RUN
), the IC enters Run Mode and
the non-ZVS protection and crest factor protection are both
enabled. The non-ZVS protection will increase the
frequency again cycle-by-cycle towards resonance from
the capacitive side. The resonant tank current will increase
again as the frequency nears resonance until the inductor
saturates again.
The crest factor protection is now enabled and measures
the instantaneous voltage at the VS pin only during the time
when LO is ‘high’ and after an initial 1us blank time from the
rising edge of LO. The blank time is necessary to prevent
the crest factor protection circuit from reacting to a non-
ZVS condition. An internal averaging circuit averages the
instantaneous voltage at the VS pin over 10 to 20 switching
cycles of LO. During Run Mode, the first time the inductor
saturates when LO is ‘high’ (after the 1us blank time) and
the peak current exceeds the average by 5 (CSCF), the
IR2520D will enter Fault Mode and both LO and HO outputs
will be latched ‘low’. The half-bridge will be safely disabled
before any damage can occur to the ballast components.
The crest factor peak-to-average fault factor varies as a
function of the internal average (Figure 20). The maximum
internal average should be below 3.0 volts. Should the
average exceed this amount, the multiplied average voltage
can exceed the maximum limit of the VS sensing circuit and
the VS sensing circuit will no longer detect crest factor
LO
I
L
V
VCO
4.6V
INDUCTIVE SIDE
OF RESONANCE
CAPACITIVE SIDE
OF RESONANCE
FREQUENCY SWEEP MODE
RUN MODE
FAULT MODE
I
MLS
AVG*5
Inductor
saturation
Fig. 8 Crest factor protection timing diagram
FAULT MODE
During Run Mode, should the VCO voltage decrease below
0.82V (V
VCOSD
) or a crest factor fault occur, the IR2520D
will enter Fault Mode (see State Diagram). The LO and HO
gate driver outputs are both latched ‘low’ so that the half-
bridge is disabled. The VCO pin is pulled low to COM and
the FMIN pin decreases from 5V to COM. VCC draws
micro-power current (I
CCFLT
) so that VCC stays at the
clamp voltage and the IC remains in Fault Mode without the
need for the charge-pump auxiliary supply. To exit Fault
Mode and return to Frequency Sweep Mode, VCC must be
cycled below the UVLO- threshold and back above the
UVLO+ threshold.
faults. This can occur when a half-bridge MOSFET is
selected that has an RDSon that is too large for the application
causing the internal average to exceed the maximum limit.
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| IR2520D | 制造商:International Rectifier 功能描述:BALLAST/BACKLIGHT CONTROLLER/DRIVER, 8 Pin, Plastic, DIP |
| IR2520DPBF | 功能描述:功率驅(qū)動(dòng)器IC 600V Ballast Cntrl IC w/Adptv 0V Switch RoHS:否 制造商:Micrel 產(chǎn)品:MOSFET Gate Drivers 類型:Low Cost High or Low Side MOSFET Driver 上升時(shí)間: 下降時(shí)間: 電源電壓-最大:30 V 電源電壓-最小:2.75 V 電源電流: 最大功率耗散: 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:SOIC-8 封裝:Tube |
| IR2520DPBF | 制造商:International Rectifier 功能描述:Controller IC Output Voltage Max.:25V |
| IR2520DS | 制造商:IRF 制造商全稱:International Rectifier 功能描述:ADAPTIVE BALLAST CONTROL IC |
| IR2520DSPBF | 功能描述:功率驅(qū)動(dòng)器IC 600V BALLAST CTRL IC ADPT ZERO VOLT RoHS:否 制造商:Micrel 產(chǎn)品:MOSFET Gate Drivers 類型:Low Cost High or Low Side MOSFET Driver 上升時(shí)間: 下降時(shí)間: 電源電壓-最大:30 V 電源電壓-最小:2.75 V 電源電流: 最大功率耗散: 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:SOIC-8 封裝:Tube |
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