参数资料
| 型号： | ADP1621ARMZ-R7 |
| 厂商： | Analog Devices Inc |
| 文件页数： | 28/32页 |
| 文件大小： | 0K |
| 描述： | IC REG CTRLR PWM CM 10-MSOP |
| 标准包装： | 1 |
| PWM 型： | 电流模式 |
| 输出数： | 1 |
| 频率 - 最大： | 1.5MHz |
| 占空比： | 97% |
| 电源电压： | 2.9 V ~ 5.5 V |
| 降压： | 是 |
| 升压： | 是 |
| 回扫： | 是 |
| 反相： | 是 |
| 倍增器： | 是 |
| 除法器： | 是 |
| Cuk： | 是 |
| 隔离： | 无 |
| 工作温度： | -40°C ~ 125°C |
| 封装/外壳： | 10-TFSOP，10-MSOP（0.118"，3.00mm 宽） |
| 包装： | 标准包装 |
| 产品目录页面： | 791 (CN2011-ZH PDF) |
| 配用： | ADP1621-EVALZ-ND - BOARD EVALUATION FOR ADP1621 |
| 其它名称： | ADP1621ARMZ-R7DKR |
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ADP1621
LED DRIVER APPLICATION CIRCUITS
The ADP1621 can be used as an LED driver. Two LED application
circuits are shown in Figure 41 and Figure 42, where each circuit
is driving 20 white LEDs in series. Each white LED has a typical
current of 150 mA at a typical forward voltage of 4.0 V, with a
maximum voltage of 4.5 V over the temperature range of ?40°C
to +125°C.
Two methods for dimming the brightness of the LEDs are
shown in Figure 41 and Figure 42. In Figure 41, a PWM signal
is fed to the SDSN pin to turn the ADP1621 controller on and
off. As a result, the LED current is turned on and off, and the
average LED current is dependent on the PWM duty cycle. The
advantage of this method is that no current flows through the
LEDs during the PWM off cycle. In addition, when the ADP1621 is
on, the forward current through the LEDs is constant, which
guarantees constant color emission across the entire dimming
range. Because the soft start period is fixed at 2048 oscillator
cycles, the PWM frequency range is limited.
As shown in Figure 41, because the natural switching frequency
chosen is 400 kHz, the useful PWM frequency range is 90 Hz to
195 Hz. However, when driving fewer LEDs, the ADP1621 can
be set to run at a faster frequency, increasing the maximum PWM
Data Sheet
where the PWM signal is filtered by an RC low-pass filter and is
fed to the FB node. The effective FB voltage at the bottom of the
LED string is modulated in an analog manner by the PWM
duty cycle. Thus, the average current through the LEDs is
modulated accordingly. Unlike the case depicted in Figure 41, a
higher duty cycle produces a lower average LED current using
the filtered PWM scheme in Figure 42. The advantage of this
circuit is that the PWM frequency can be in the range between
90 Hz and 100 kHz, and the duty cycle can be between 5% and
95%. The disadvantage of this method is that the forward
current through the LEDs is directly modified to control the
brightness of the LEDs. Because the wavelength of the light
emitted from an LED is a weak function of its forward current,
perfect color purity across the entire dimming range cannot be
guaranteed.
If PCB space is a constraint, smaller inductors can be selected
for the circuits shown in Figure 41 and Figure 42. For example,
a 4.7 μH inductor can be used, and a 200 kHz switching fre-
quency can be selected. However, with this small inductor, the
system operates in DCM, which is slightly less efficient than
operating in CCM.
frequency. The PWM duty cycle can be between 5% and 95%. A
higher PWM duty cycle produces a higher average LED current.
Rev. B | Page 28 of 32
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相关代理商/技术参数 |
参数描述 |
|---|---|
| ADP1621-BL2-EVZ | 制造商:Analog Devices 功能描述:BLANK ADISIMPOWER EVAL ADP1621 - Boxed Product (Development Kits) |
| ADP1621-BL4-EVZ | 功能描述:BOARD EVALUATION FOR ADP1621 RoHS:是 类别:编程器，开发系统 >> 评估板 - DC/DC 与 AC/DC（离线）SMPS 系列:- 标准包装:1 系列:- 主要目的:DC/DC，步降 输出及类型:1，非隔离 功率 - 输出:- 输出电压:3.3V 电流 - 输出:3A 输入电压:4.5 V ~ 28 V 稳压器拓扑结构:降压 频率 - 开关:250kHz 板类型:完全填充 已供物品:板 已用 IC / 零件:L7981 其它名称:497-12113STEVAL-ISA094V1-ND |
| ADP1621-EVAL | 制造商:AD 制造商全称:Analog Devices 功能描述:Constant-Frequency, Current-Mode Step-Up DC/DC Controller |
| ADP1621-EVALZ | 功能描述:BOARD EVALUATION FOR ADP1621 RoHS:是 类别:编程器，开发系统 >> 评估板 - DC/DC 与 AC/DC（离线）SMPS 系列:- 标准包装:1 系列:- 主要目的:DC/DC，步降 输出及类型:1，非隔离 功率 - 输出:- 输出电压:3.3V 电流 - 输出:3A 输入电压:4.5 V ~ 28 V 稳压器拓扑结构:降压 频率 - 开关:250kHz 板类型:完全填充 已供物品:板 已用 IC / 零件:L7981 其它名称:497-12113STEVAL-ISA094V1-ND |
| ADP162ACBZ-1.2-R7 | 功能描述:IC REG LDO 1.2V .15A 4WLCSP RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - 线性 系列:- 其它有关文件:LD39015JXX12 View All Specifications 标准包装:1 系列:- 稳压器拓扑结构:正，固定式 输出电压:1.2V 输入电压:1.5 V ~ 5.5 V 电压 - 压降（标准）:- 稳压器数量:1 电流 - 输出:150mA 电流 - 限制（最小）:- 工作温度:-40°C ~ 125°C 安装类型:表面贴装 封装/外壳:4-WFBGA，FCBGA 供应商设备封装:4-覆晶（1.07x1.07） 包装:Digi-Reel® 其它名称:497-11958-6 |
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