- 您现在的位置：买卖IC网 > PDF目录15036 > MAX17499BEUB+T (Maxim Integrated Products)IC REG CTRLR BST ISO PWM 10-UMAX PDF资料下载
参数资料
| 型号： | MAX17499BEUB+T |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 11/18页 |
| 文件大小： | 0K |
| 描述： | IC REG CTRLR BST ISO PWM 10-UMAX |
| 产品培训模块： | Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| 标准包装： | 2,500 |
| PWM 型： | 电流模式 |
| 输出数： | 1 |
| 频率 - 最大： | 625kHz |
| 占空比： | 75% |
| 电源电压： | 9.5 V ~ 24 V |
| 降压： | 无 |
| 升压： | 是 |
| 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 ~ 125°C |
| 封装/外壳： | 10-TFSOP，10-MSOP（0.118"，3.00mm 宽） |
| 包装： | 带卷 (TR) |
Current-Mode PWM Controllers with
Programmable Switching Frequency
Soft-Start
The devices’ soft-start feature allows the output voltage
to ramp up in a controlled manner, eliminating voltage
overshoot. The devices ’ reference generator that is
internally connected to the error amplifier soft-starts to
achieve superior control of the output voltage under
heavy- and light-load conditions. Soft-start begins after
UVLO is deasserted (V IN is above 21.6V for the
MAX17500, V IN is above 9.5V for the MAX17499, and
the voltage on UVLO/EN is above 1.23V). The voltage
applied to the noninverting node of the amplifier ramps
from 0 to 1.23V in 1984 NDRV switching cycles. Use the
following formula to calculate the soft-start time (t SS ):
MAX17499/MAX17500 fig04
100mA LOAD ON/V OUT1
100mA LOAD ON/V OUT2
V OUT
2V/div
t SS =
1984
f NDRV
2ms/div
Figure 4. Primary-Side Output Voltage Soft-Start During Initial
R 15 = 88 . 9 × ( R 12 ) 4
where f NDRV is the switching frequency at the NDRV
output. Figure 4 shows the soft-start regulated output of
a power supply using the MAX17500 during startup.
n-Channel MOSFET Switch Driver
The NDRV output drives an external n-channel MOSFET.
The internal regulator output (V CC ), set to approximately
9V, drives NDRV. For the universal input voltage range,
the MOSFET used must withstand the DC level of the
high-line input voltage plus the reflected voltage at the
primary of the transformer. Most applications that use the
discontinuous flyback topology require a MOSFET rated
at 600V. NDRV can source/sink in excess of 650mA/
1000mA peak current; therefore, select a MOSFET that
mA yields acceptable conduction and switching losses.
Oscillator/Switching Frequency
Use an external resistor at RT to program the devices’
internal oscillator frequency between 50kHz and 2.5MHz.
The MAX17499A/MAX17500A output switching frequen-
cy is one-half the programmed oscillator frequency with a
Startup for the Circuit in Figure 6
where R12 is the resistor connected from RT to GND
(see Figure 1).
Connect an RC network in parallel with R12 as shown in
Figure 1. The RC network should consist of a 100nF
capacitor, C6, (for stability) in series with resistor R15,
which serves to further minimize jitter. Use the following
formula to determine the value of R15:
1
For example, if R12 is 4k Ω , R15 becomes 707 Ω .
Internal Error Amplifier
The devices include an internal error amplifier to regu-
late the output voltage in the case of a nonisolated
power supply (see Figure 1). For the circuit in Figure 1,
calculate the output voltage using the following equation:
V OUT = ? 1 +
50% duty cycle. The MAX17499B/MAX17500B output
switching frequency is one-quarter of the programmed
oscillator frequency with a 75% duty cycle.
?
?
R13 ?
R 14 ? ?
V REF
The MAX17499A/MAX17500A and MAX17499B/
MAX17500B have programmable output switching fre-
quencies from 25kHz to 625kHz and 12.5kHz to
625kHz, respectively. Use the following formulas to
determine the appropriate value of resistor R12 (see
Figure 1) needed to generate the desired output
switching frequency (f SW ) at the NDRV output:
where V REF = 1.23V. The amplifier’s noninverting input
is internally connected to a digital soft-start circuit that
gradually increases the reference voltage during start-
up applied to this input. This forces the output voltage
to come up in an orderly and well-defined manner
under all load conditions.
The error amplifier may also be used to regulate the ter-
R 12 =
R 12 =
10 10
2 f SW
10 10
4 f SW
for the MAX 17499 A MAX 17500 A .
for the MAX 17499 B MAX 17500 B .
tiary winding output, which implements a primary-side-
regulated, isolated power supply (see Figure 6). For the
______________________________________________________________________________________
11
相关PDF资料 |
PDF描述 |
|---|---|
| H2ABG-10102-B4-ND | JUMPER-H1503TR/A2015B/H1501TR 2" |
| DS1233-15+T&R/STR | IC ECONORESET NO PBR 15% TO92-3 |
| H2ABG-10102-A4-ND | JUMPER-H1503TR/A2015A/H1501TR 2" |
| VE-21T-EW-F3 | CONVERTER MOD DC/DC 6.5V 100W |
| EBC65DRTS-S13 | CONN EDGECARD 130POS .100 EXTEND |
相关代理商/技术参数 |
参数描述 |
|---|---|
| MAX1749EUK | 制造商:Maxim Integrated Products 功能描述:SOT23 VIBRATOR MOTOR DRIVER - Rail/Tube |
| MAX1749EUK+ | 制造商:Maxim Integrated Products 功能描述:STD REG 1.25V TO 6.5V/1.25V 0.12A 5PIN SOT-23 - Rail/Tube |
| MAX1749EUK+T | 功能描述:马达/运动/点火控制器和驱动器 Vibrator Motor Driver RoHS:否 制造商:STMicroelectronics 产品:Stepper Motor Controllers / Drivers 类型:2 Phase Stepper Motor Driver 工作电源电压:8 V to 45 V 电源电流:0.5 mA 工作温度:- 25 C to + 125 C 安装风格:SMD/SMT 封装 / 箱体:HTSSOP-28 封装:Tube |
| MAX1749EUK-T | 功能描述:马达/运动/点火控制器和驱动器 Vibrator Motor Driver RoHS:否 制造商:STMicroelectronics 产品:Stepper Motor Controllers / Drivers 类型:2 Phase Stepper Motor Driver 工作电源电压:8 V to 45 V 电源电流:0.5 mA 工作温度:- 25 C to + 125 C 安装风格:SMD/SMT 封装 / 箱体:HTSSOP-28 封装:Tube |
| MAX174ACPI | 功能描述:模数转换器 - ADC RoHS:否 制造商:Texas Instruments 通道数量:2 结构:Sigma-Delta 转换速率:125 SPs to 8 KSPs 分辨率:24 bit 输入类型:Differential 信噪比:107 dB 接口类型:SPI 工作电源电压:1.7 V to 3.6 V, 2.7 V to 5.25 V 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:VQFN-32 |
发布紧急采购，3分钟左右您将得到回复。