参数资料
| 型号： | ISL78200AVEZ |
| 厂商： | Intersil |
| 文件页数： | 16/22页 |
| 文件大小： | 0K |
| 描述： | IC REG BUCK BOOST SYNC 20HTSSOP |
| 标准包装： | 740 |
| 类型： | 降压（降压），升压（升压） |
| 输出类型： | 可调式 |
| 输出数： | 1 |
| 输出电压： | 可调至 0.8V |
| 输入电压： | 3 V ~ 40 V |
| PWM 型： | 电流模式 |
| 频率 - 开关： | 200kHz ~ 2.2MHz |
| 电流 - 输出： | 2.5A |
| 同步整流器： | 两者兼有 |
| 工作温度： | -40°C ~ 105°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 20-TSSOP（0.173"，4.40mm 宽） |
| 包装： | 管件 |
| 供应商设备封装： | 20-HTSSOP |
ISL78200
the boost input power source is turned off. At boost mode
ground. Use Equation 10 to calculate the resistor.
R LIM = ---------------------------------------
applications where there is no external control signal to
enable/disable the IC, an external input UVLO circuit must be
implemented for the start-up and shutdown sequence.
300000
I OC [ A ] + 0.018
(EQ. 10)
PFM is not available in boost mode.
Oscillator and Synchronization
The oscillator has a default frequency of 500kHz with the FS pin
connected to VCC, ground, or floating. The frequency can be
programmed to any frequency between 200kHz and 2.2MHz with
a resistor from the FS pin to GND.
Note that with the lower R LIM , I OC1 is higher. Considering the OC
programming circuit tolerances over temperature range -40°C to
+105°C, 71.5k is the lowest resistor value recommended to be
used for R LIM to achieve highest OC threshold. With 71.5k R LIM ,
the OC limit is 4.18A (TYP). Resistor lower than 71.5k would
result in default 3.6A OC1 threshold.
370
R FS [ k Ω ] = --------------------------------------------------------------
145000 – 16 ? FS [ kHz ]
FS [ kHz ]
(EQ. 9)
320
The SYNC pin is bi-directional and it outputs the IC’s default or
programmed local clock signal when it’s free running. The IC
locks to an external clock injected to SYNC pin (external clock
frequency recommended to be 10% higher than the free running
frequency). The delay from the rising edge of the external clock
signal to the PHASE rising edge is half of the free running switching
period pulse 220ns, (0.5Tsw+220ns). The maximum external clock
frequency is recommended to be 1.6 of the free running frequency.
270
220
170
120
When the part enters PFM pulse skipping mode, the
synchronization function is shut off and also no clock signal
output in SYNC pin.
70
0.0
1.0
2.0 3.0 4.0
I OC1 (A)
FIGURE 31. R LIM vs I OC1
5.0
6.0
With the SYNC pins simply connected together, multiple
ISL78200s can be synchronized. The slave ICs automatically
have 180° phase shift respect to the master IC.
1200
1000
800
600
400
200
The second current protection threshold, I OC2 , is 15% higher
than I OC1 mentioned above. At the instant the high-side MOSFET
current reaches I OC2 , the PWM shuts off after a 2 cycle delay and
the IC enters hiccup mode. In hiccup mode, the PWM is disabled
for a dummy soft-start duration equal to 5 regular soft-start
periods. After this dummy soft-start cycle, the true soft-start cycle
is attempted again. The I OC2 offers a robust and reliable
protection against worst case conditions.
The frequency fold back is implemented for the ISL78200. When
overcurrent limiting, the switching frequency is reduced to
proportional to the output voltage in order to keep the inductor
current under the limit threshold during overload condition. The
low limit of frequency under frequency foldback is 40kHz.
Overvoltage Protection
0
0
500 1000 1500
F S (kHz)
FIGURE 30. R FS vs FREQUENCY
2000
2500
If the voltage detected on the FB pin is over 110% of reference,
the high-side and low-side drivers shut down immediately and
won’t be allowed on until the FB voltage falls down to 0.8V. When
the FB voltage drops to 0.8V, the drivers are released on. If the
Fault Protection
Overcurrent Protection
The overcurrent function protects against any overload condition
and output shorts at worst case, by monitoring the current
flowing through the upper MOSFET.
There are 2 current limiting thresholds. The first one, I OC1 , is to
limit the high-side MOSFET peak current cycle-by-cycle. The
current limit threshold is set to default at 3.6A with the ILIMIT pin
connected to GND or VCC, or left open. The current limit threshold
can also be programmed by a resistor, R LIM , at the ILIMIT pin to
16
120% overvoltage threshold is reached, the high-side and
low-side driver shut down immediately and the IC is latched off.
The IC has to be reset for restart.
Thermal Protection
The ISL78200 PWM will be disabled if the junction temperature
reaches +155°C. A +15°C hysteresis insures that the device will
not restart until the junction temperature drops below +140°C.
Component Selections
ISL78200 iSim model available in internet can be used to
simulate the operating behaviors to assist the design.
FN7641.2
December 24, 2013
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相关代理商/技术参数 |
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|---|---|
| ISL78200AVEZ-T | 功能描述:IC REG BUCK BOOST SYNC 20HTSSOP RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 开关稳压器 系列:- 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:2,500 系列:- 类型:降压（降压） 输出类型:两者兼有 输出数:1 输出电压:5V，1 V ~ 10 V 输入电压:3.5 V ~ 28 V PWM 型:电流模式 频率 - 开关:220kHz ~ 1MHz 电流 - 输出:600mA 同步整流器:无 工作温度:-40°C ~ 125°C 安装类型:表面贴装 封装/外壳:16-SSOP（0.154"，3.90mm 宽） 包装:带卷 (TR) 供应商设备封装:16-QSOP |
| ISL78201AVEZ-T | 制造商:Intersil Corporation 功能描述:2.5A SYNC BUCK W PRE-BOOST REG, 20LD HTSSOP 4.4MM, T&R - Tape and Reel |
| ISL78201AVEZ-TR5303 | 制造商:Intersil Corporation 功能描述: 制造商:Intersil Corporation 功能描述:HARMAN BECKER ISL78201AVEZ-T W/SPECIAL CHANGE CONTROL, 12 MO - Tape and Reel |
| ISL78205 | 制造商:INTERSIL 制造商全称:Intersil Corporation 功能描述:2.5A Buck Controller with Integrated High-Side MOSFET |
| ISL78205AVEZ | 功能描述:IC REG BUCK SYNC ADJ 20HTSSOP RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 开关稳压器 系列:- 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:2,500 系列:- 类型:降压（降压） 输出类型:两者兼有 输出数:1 输出电压:5V，1 V ~ 10 V 输入电压:3.5 V ~ 28 V PWM 型:电流模式 频率 - 开关:220kHz ~ 1MHz 电流 - 输出:600mA 同步整流器:无 工作温度:-40°C ~ 125°C 安装类型:表面贴装 封装/外壳:16-SSOP（0.154"，3.90mm 宽） 包装:带卷 (TR) 供应商设备封装:16-QSOP |
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