参数资料
| 型号： | UCC28250PW |
| 厂商： | Texas Instruments |
| 文件页数： | 31/53页 |
| 文件大小： | 0K |
| 描述： | IC REG CTRLR PWM CM/VM 20-TSSOP |
| 标准包装： | 70 |
| PWM 型： | 电流/电压模式 |
| 输出数： | 1 |
| 频率 - 最大： | 1MHz |
| 占空比： | 100% |
| 电源电压： | 4.7 V ~ 17 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： | 无 |
| 工作温度： | -40°C ~ 125°C |
| 封装/外壳： | 20-TSSOP（0.173"，4.40mm 宽） |
| 包装： | 管件 |
| 其它名称： | 296-27776-5 UCC28250PW-ND |
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SLUSA29C – APRIL 2010 – REVISED JULY 2011
APPLICATION INFORMATION
The UCC28250 is a high performance PWM controller with advanced synchronous rectifier outputs and is ideally
suited for regulated half-bridge, full-bridge and push-pull converters. A dedicated internal pre-biased start up
control loop working in conjunction with a primary-side voltage loop achieves monotonic pre-biased start up for
either primary-side or secondary-side control applications. The UCC28250 architecture allows either voltage
mode or current mode control.
Input voltage feedforward can be implemented, allowing PWM ramp generator to improve the converter line
transient response. Advanced cycle-by-cycle current limit achieves volt-second balancing even during fault
conditions. The hiccup timer helps the system to stay within a safe operation range under over load conditions.
With a multifunction OVP/OTP pin, combinations of input voltage protection, output voltage protection and over
temperature protection can be implemented. The UCC28250 allows individual programming of dead time
between primary-side switch and secondary-side SRs, in order to allow optimal power stage design. Dead time
can also be reduced to zero, and this allows optimal system configuration considering the delays on the gate
driver stage. The UCC28250 also provides complete system level protection functions, including UVLO, thermal
shut down and over voltage, over current protection.
Error Amplifier and PWM Generation
The UCC28250 includes a high performance internal error amplifier with low input offset, high source/sink current
capability and high gain bandwidth (typical 3.5 MHz). The reference of the error amplifier (REF/EA+ pin) is set
externally to support flexible trimming of the voltage loop, and to make the controller flexible for both primary
side, as well as secondary-side control. The extra positive input for the error amplifier is the SS pin which is used
to externally program the soft-start time of the converter ’ s output.
During steady state operation, the primary switch duty cycle, D, is generated based on the external ramp on
RAMP/CS pin and the COMP pin voltage. A higher COMP pin voltage results in a larger duty cycle. The
secondary-side SR duty cycle is SR_D = (1-D), complementary to the primary-side duty cycle, without
considering the dead time between primary-side switch and secondary-side SR. The primary outputs begin to
switch when COMP pin voltage is above the 350 mV internal offset. The synchronous rectifier outputs only switch
after COMP pin voltage is above 550 mV internal offset. According to the internal logic, the minimum pulse width
for the primary-side OUTA and OUTB is typically 100 ns.
During soft start, the primary-side switch duty cycle is generated based on the external ramp on RAMP/CS pin
and the COMP pin voltage. However, the duty cycle of secondary-side SR is generated based on an internal
ramp and the COMP pin voltage. When the converter is controlled on the primary side, an internal ramp is a
fixed ramp with 3-V peak voltage. When the converter is controlled on secondary side, an internal ramp is
generated based on the internal pre-biased start-up loop. An internal pre-biased start-up loop modifies the SR
duty cycle during soft start to achieve the optimal pre-biased start-up performance.
After the SS pin reaches 2.9 V, the pre-biased start-up control loop is disabled. The secondary-side SR
instantaneously changes into its steady state value as complementary to the primary-side duty cycle.
Copyright ? 2010 – 2011, Texas Instruments Incorporated
Product Folder Link(s): UCC28250
31
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相关代理商/技术参数 |
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|---|---|
| UCC28250PW | 制造商:Texas Instruments 功能描述:PWM CONTROLLER IC 17V TSSOP-20 制造商:Texas Instruments 功能描述:IC, PWM CONTROLLER, 17V, TSSOP-20 |
| UCC28250PWR | 功能描述:电压模式 PWM 控制器 Adv PWM Controller 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 |
| UCC28250PWT | 制造商:TI 制造商全称:Texas Instruments 功能描述:Advanced PWM Controller With Pre-Bias Operation |
| UCC28250RGPR | 功能描述:电压模式 PWM 控制器 Adv PWM Controller 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 |
| UCC28250RGPT | 功能描述:电压模式 PWM 控制器 Adv PWM Controller 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 |
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