收藏本站
Application Note 1247
The ISL6521EVAL1 is designed with a room temperature
overcurrent trip point of 7A. The trip point is set by the
OCSET resistor and is established relative to the r DS(on) of
the upper MOSFET. See the product datasheet for additional
information on setting this trip point.
The linear controllers feature undervoltage protection which
also provide overcurrent protection. A low impedance short on
a linear output will cause the output voltage to sag. When the
output voltage drops below 70% of the output voltage set point,
the linear controller shuts down. The linear controller then
In Figure 7, the output voltage rises in response to the
removal of load and the inductor begins to slew down to the
original load level. The controller detects the output voltage
rise and immediately decreases the upper gate pulse width.
The PHASE waveform shows that upper gate is not turned
on for three to four cycles as the inductor sheds load. The
upper gate pulse width is then narrow for the next few cycles
as the inductor slowly picks up load current. The output
voltage quickly settles back to the +1.5V set point.
enters a wait period equivalent to three soft-start intervals. A
soft-start interval follows and if the undervoltage condition
remains, the linear controller will shutdown during soft-start.
Until successful, the linear controller will attempt to restart the
output in the same hiccup mode style outlined above.
Shutdown on any one output does not shutdown all outputs.
Transient Response
FPGA transient specifications vary depending on overall
gate usage. The ISL6521EVAL1 is designed to meet a load
step of 5A with a slew rate of 2.5A/ μ s. During a transient, the
FPGA core voltage (VOUT1) must not exceed ±50mV of
+1.5V. The leading edge transient response of the
ISL6521EVAL1 to the aforementioned load is shown in
Figure 6. The core voltage waveform is offset to +1.5V.
1.5V
10 μ s/div
VOUT1, 50mV/div
PHASE, 5V/div
IOUT1, 5A/div
FIGURE 7. TRAILING EDGE TRANSIENT RESPONSE
1.5V
VOUT1, 50mV/div
PHASE, 5V/div
IOUT1, 5A/div
The leading edge transient response is less than 30 μ s and
the trailing edge transient response is less than 20 μ s.
Achieving a faster transient response time means reducing
the output inductance. The lower inductance would allow the
inductor current to transition faster as load current changes.
The main trade-off in speeding up transient response is a
drop in efficiency due to the reduced inductance.
Efficiency
The performance of the ISL6521EVAL1 board, loaded from
1A to 6A, is plotted in Figure 8. Measurements were taken at
95
10 μ s/div
FIGURE 6. LEADING EDGE TRANSIENT RESPONSE
The core voltage sags as the inductor current begins to slew
in response to the changing load current. The controller
detects the new load level by the drop in output voltage and
responds by increasing the pulse width to the upper
MOSFET. The bulk output capacitors support the load as the
inductor slews. The increase in duty cycle can be seen
looking at the PHASE waveform just before, during, and
after the transient edge reaches 5A. The inductor current
rapidly increases to meet the new demand, supplying an
90
85
80
75
increasing portion of the load. The output voltage returns to
the +1.5V set point as the inductor picks up the load again.
70
1
2
3 4
OUTPUT CURRENT (A)
5
6
FIGURE 8. EFFICIENCY vs LOAD CURRENT
3
AN1247.0
July 10, 2006
发布紧急采购，3分钟左右您将得到回复。

采购需求

(若只采购一条型号，填写一行即可)

发布成功！您可以继续发布采购。也可以进入我的后台，查看报价

发布成功！您可以继续发布采购。也可以进入我的后台，查看报价

*型号 *数量 厂商 批号 封装
添加更多采购

我的联系方式

*
*
*
相关PDF资料
ISL6531EVAL2 EVALUATION BOARD 2 ISL6531
ISL6700EVAL1Z EVALUATION BOARD FOR ISL6700
ISL6844EVAL1 EVALUATION BOARD 1 ISL6844
ISL6AHPEVAL1 EVAL BOARD HIP1011D/ISL6118
ISL70218SRHMEVAL1Z EVALUATION BOARD FOR ISL70218SRH
ISL8107EVAL1Z EVAL BOARD FOR ISL8107
ISL88550AEVAL1 EVALUATION BOARD 1 ISL88550A
ISL88694EVAL EVALUATION BOARD ISL88694
相关代理商/技术参数
ISL6521EVAL1Z 功能描述:EVALUATION BOARD 1 ISL6521 RoHS:是 类别:编程器，开发系统 >> 评估板 - DC/DC 与 AC/DC（离线）SMPS 系列:- 产品培训模块:Obsolescence Mitigation Program 标准包装:1 系列:True Shutdown™ 主要目的:DC/DC，步升 输出及类型:1，非隔离 功率 - 输出:- 输出电压:- 电流 - 输出:1A 输入电压:2.5 V ~ 5.5 V 稳压器拓扑结构:升压 频率 - 开关:3MHz 板类型:完全填充 已供物品:板 已用 IC / 零件:MAX8969
ISL6521IBZ 功能描述:电压模式 PWM 控制器 4 IN 1 PWM/LINEAR CNTRLR 5V RoHS:否 制造商:Texas Instruments 输出端数量:1 拓扑结构:Buck 输出电压:34 V 输出电流: 开关频率: 工作电源电压:4.5 V to 5.5 V 电源电流:600 uA 最大工作温度:+ 125 C 最小工作温度:- 40 C 封装 / 箱体:WSON-8 封装:Reel
ISL6521IBZ-T 功能描述:电压模式 PWM 控制器 4 IN 1 PWM/LINEAR CNTRLR 5V RoHS:否 制造商:Texas Instruments 输出端数量:1 拓扑结构:Buck 输出电压:34 V 输出电流: 开关频率: 工作电源电压:4.5 V to 5.5 V 电源电流:600 uA 最大工作温度:+ 125 C 最小工作温度:- 40 C 封装 / 箱体:WSON-8 封装:Reel
ISL6522ACB 功能描述:IC REG CTRLR BST PWM VM 14-SOIC RoHS:否 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:- 标准包装:4,000 系列:- PWM 型:电压模式 输出数:1 频率 - 最大:1.5MHz 占空比:66.7% 电源电压:4.75 V ~ 5.25 V 降压:是 升压:无 回扫:无 反相:无 倍增器:无 除法器:无 Cuk:无 隔离:无 工作温度:-40°C ~ 85°C 封装/外壳:40-VFQFN 裸露焊盘 包装:带卷 (TR)
ISL6522ACB-T 功能描述:IC REG CTRLR BST PWM VM 14-SOIC RoHS:否 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:- 标准包装:4,000 系列:- PWM 型:电压模式 输出数:1 频率 - 最大:1.5MHz 占空比:66.7% 电源电压:4.75 V ~ 5.25 V 降压:是 升压:无 回扫:无 反相:无 倍增器:无 除法器:无 Cuk:无 隔离:无 工作温度:-40°C ~ 85°C 封装/外壳:40-VFQFN 裸露焊盘 包装:带卷 (TR)
ISL6522ACR 功能描述:IC REG CTRLR BST PWM VM 16-QFN RoHS:否 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:- 标准包装:4,000 系列:- PWM 型:电压模式 输出数:1 频率 - 最大:1.5MHz 占空比:66.7% 电源电压:4.75 V ~ 5.25 V 降压:是 升压:无 回扫:无 反相:无 倍增器:无 除法器:无 Cuk:无 隔离:无 工作温度:-40°C ~ 85°C 封装/外壳:40-VFQFN 裸露焊盘 包装:带卷 (TR)
ISL6522ACR-T 功能描述:IC REG CTRLR BST PWM VM 16-QFN RoHS:否 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:- 标准包装:4,000 系列:- PWM 型:电压模式 输出数:1 频率 - 最大:1.5MHz 占空比:66.7% 电源电压:4.75 V ~ 5.25 V 降压:是 升压:无 回扫:无 反相:无 倍增器:无 除法器:无 Cuk:无 隔离:无 工作温度:-40°C ~ 85°C 封装/外壳:40-VFQFN 裸露焊盘 包装:带卷 (TR)
ISL6522BCB 功能描述:IC REG CTRLR BST PWM VM 14-SOIC RoHS:否 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:- 标准包装:4,000 系列:- PWM 型:电压模式 输出数:1 频率 - 最大:1.5MHz 占空比:66.7% 电源电压:4.75 V ~ 5.25 V 降压:是 升压:无 回扫:无 反相:无 倍增器:无 除法器:无 Cuk:无 隔离:无 工作温度:-40°C ~ 85°C 封装/外壳:40-VFQFN 裸露焊盘 包装:带卷 (TR)