参数资料
型号: ZL2008ALAFT
厂商: Intersil
文件页数: 26/42页
文件大小: 0K
描述: IC REG CTRLR BUCK PWM VM 36-QFN
标准包装: 100
PWM 型: 电压模式
输出数: 1
频率 - 最大: 1.4MHz
占空比: 95%
电源电压: 3 V ~ 5.5 V
降压:
升压:
回扫:
反相:
倍增器:
除法器:
Cuk:
隔离:
工作温度: -40°C ~ 85°C
封装/外壳: 36-VFQFN 裸露焊盘
包装: 带卷 (TR)
ZL2008
Please refer to Application Note AN2033 for details on how to
configure the UVLO threshold or to select specific UVLO fault
response options via the I 2 C/SMBus interface.
Output Overvoltage Protection
The ZL2008 offers an internal output overvoltage protection
circuit that can be used to protect sensitive load circuitry from
being subjected to a voltage higher than its prescribed limits. A
hardware comparator is used to compare the actual output
voltage (seen at the VSEN pin) to a threshold set to 15% higher
than the target output voltage (the default setting). If the VSEN
voltage exceeds this threshold, the PG pin will de-assert and the
device can then respond in a number of ways as follows:
1. Initiate an immediate shutdown until the fault has been
cleared. The user can select a specific number of retry
attempts.
2. Turn off the high-side MOSFET and turn on the low-side
MOSFET. The low-side MOSFET remains ON until the device
attempts a restart.
The default response from an overvoltage fault is to immediately
shut down. The device will continuously check for the presence of
the fault condition, and when the fault condition no longer exists
the device will be re-enabled.
For continuous overvoltage protection when operating from an
external clock, the only allowed response is an immediate
shutdown.
Please refer to Application Note AN2033 for details on how to
select specific overvoltage fault response options via I 2 C/SMBus.
Output Pre-Bias Protection
An output pre-bias condition exists when an externally applied
voltage is present on a power supply’s output before the power
supply’s control IC is enabled. Certain applications require that
the converter not be allowed to sink current during start up if a
pre-bias condition exists at the output. The ZL2008 provides
pre-bias protection by sampling the output voltage prior to
initiating an output ramp.
If a pre-bias voltage lower than the target voltage exists after the
pre-configured delay period has expired, the target voltage is set
to match the existing pre-bias voltage and both drivers are
enabled. The output voltage is then ramped to the final
regulation value at the ramp rate set by the SS pin.
The actual time the output will take to ramp from the pre-bias
voltage to the target voltage will vary depending on the pre-bias
voltage but the total time elapsed from when the delay period
expires and when the output reaches its target value will match
the pre-configured ramp time. See Figure 19.
If a pre-bias voltage higher than the target voltage exists after the
pre-configured delay period has expired, the target voltage is set
to match the existing pre-bias voltage and both drivers are
enabled with a PWM duty cycle that would ideally create the
pre-bias voltage.
Once the pre-configured soft-start ramp period has expired, the
PG pin will be asserted (assuming the pre-bias voltage is not
higher than the overvoltage limit). The PWM will then adjust its
26
duty cycle to match the original target voltage and the output will
ramp down to the pre-configured output voltage.
FIGURE 19. Output Responses to Pre-bias Voltages
If a pre-bias voltage higher than the overvoltage limit exists, the
device will not initiate a turn-on sequence and will declare an
overvoltage fault condition to exist. In this case, the device will
respond based on the output overvoltage fault response method
that has been selected. See “Output Overvoltage Protection” on
page 26 for response options due to an overvoltage condition.
Pre-bias protection is not offered for current sharing groups that
also have tracking enabled.
Output Overcurrent Protection
The ZL2008 can protect the power supply from damage if the
output is shorted to ground or if an overload condition is imposed
on the output. Once the current limit threshold has been selected
(see “Current Limit Threshold Selection” on page 21), the user
may determine the desired course of action in response to the
fault condition. The following overcurrent protection response
options are available:
1. Initiate a shutdown and attempt to restart an infinite number
of times with a preset delay period between attempts.
2. Initiate a shutdown and attempt to restart a preset number of
times with a preset delay period between attempts.
3. Continue operating for a given delay period, followed by
shutdown if the fault still exists.
FN6859.4
April 29, 2011
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ZL2008ALAFT1 功能描述:IC REG CTRLR BUCK PWM VM 36-QFN RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:- 标准包装:2,500 系列:- PWM 型:电流模式 输出数:1 频率 - 最大:500kHz 占空比:100% 电源电压:8.2 V ~ 30 V 降压:无 升压:无 回扫:是 反相:无 倍增器:无 除法器:无 Cuk:无 隔离:是 工作温度:0°C ~ 70°C 封装/外壳:8-DIP(0.300",7.62mm) 包装:管件 产品目录页面:1316 (CN2011-ZH PDF)
ZL2008ALBFT 功能描述:IC REG CTRLR BUCK PWM VM 36-QFN RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:- 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:2,500 系列:- PWM 型:电流模式 输出数:1 频率 - 最大:275kHz 占空比:50% 电源电压:18 V ~ 110 V 降压:无 升压:无 回扫:无 反相:无 倍增器:无 除法器:无 Cuk:无 隔离:是 工作温度:-40°C ~ 85°C 封装/外壳:8-SOIC(0.154",3.90mm 宽) 包装:带卷 (TR)
ZL2008ALBFT1 功能描述:IC REG CTRLR BUCK PWM VM 36-QFN RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:- 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:2,500 系列:- PWM 型:电流模式 输出数:1 频率 - 最大:275kHz 占空比:50% 电源电压:18 V ~ 110 V 降压:无 升压:无 回扫:无 反相:无 倍增器:无 除法器:无 Cuk:无 隔离:是 工作温度:-40°C ~ 85°C 封装/外壳:8-SOIC(0.154",3.90mm 宽) 包装:带卷 (TR)
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