AN1021
To observe the output while the regulator sinks current,
connect the positive terminal of the load to the 3.3V post
(J1). Connect the return terminal of the same load to the
V OUT post (J3).
Startup
There are two distinct start up methods for both the ISL6526
and ISL6527 regulators. The first method is invoked through
the application of power to the IC. The soft-start feature
allows for a controlled rise of the output once the Power On
Reset (POR) threshold of the input voltage has been
reached. Figure 1 shows the start up profile of the regulator
in relation to the start up of the 3.3V input supply and the
bias supply generated by the charge pump. Both the
ISL6526 and ISL6527, whether switching at 300 or 600kHz,
Shutdown
As discussed in the previous section, if the OCSET/SD pin
or ENABLE pin is pulled down and held below 0.8V, the
regulator will be turned off. The MOSFET gates are
immediately pulled low. Figure 3 shows the shutdown profile
of the regulator under full load.
V OUT
will have the same start up profile as shown in Figure 1.
V ENABLE
1V/DIV
1V/DIV
V CPVOUT
1V/DIV
20 μ s/DIV
FIGURE 3. SHUTDOWN WITH FULL LOAD (ISL6526)
V VCC
1V/DIV
V OUT
1V/DIV
2ms/DIV
FIGURE 1. START UP FROM POR
The second method of start up is through the use of the
Enable/Shutdown feature. Holding the ENABLE pin on the
ISL6526 or the OCSET/SD pin on the ISL6527 below 0.8V
ISL6527 Input Reference
A distinguishing feature of the ISL6527 is that the reference
used to regulate the output is provided from an external
source. This allows the converter to track the output of
another regulator at any desired ratio or amplify a small
signal. Figure 4 illustrates the tracking and power
amplification ability of the ISL6527 with a sinusoidal
reference. Figure 4 also illustrates the startup profile.
V REF_IN
200mV/DIV
will disable the regulator by forcing both the upper and lower
MOSFETs off. Releasing the respective pin allows the
regulator to start up. Figure 2 shows the start up profile with
this method.
V OUT
200mV/DIV
V ENABLE
1V/DIV
2ms/DIV
FIGURE 4. SMALL SIGNAL POWER AMPLIFICATION
V OUT
1V/DIV
1ms/DIV
FIGURE 2. START UP FROM SHUT DOWN
2
Ripple Voltage
Figure 5 shows the ripple voltage on the output of the
regulator. The ripple voltages shown are for both the
ISL6526 and ISL6527 ICs running at either 300 or 600kHz.
相关PDF资料
GBB15DHHD CONN EDGECARD 30POS .050 DIP SLD
695D475X9020D2T CAP TANT 4.7UF 20V 10% 1810
594D336X9016B8T CAP TANT 33UF 16V 10% 1611
ISL6439EVAL1 EVALUATION BOARD 1 ISL6439
695D475X0020D2T CAP TANT 4.7UF 20V 20% 1810
695D475X0015D2T CAP TANT 4.7UF 15V 20% 1810
TARS685M025 CAP TANT 6.8UF 25V 20% AXIAL
EBC13DRTI CONN EDGECARD 26POS DIP .100 SLD
相关代理商/技术参数
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ISL6526IB-T 功能描述:IC REG CTRLR BUCK 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)
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ISL6526IBZ-T 功能描述:IC REG CTRLR BUCK PWM VM 14-SOIC 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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ISL6526IR-TR51 制造商:Intersil Corporation 功能描述: