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| 型号： | TL2575HV-05IKTTRG3 |
| 厂商： | TEXAS INSTRUMENTS INC |
| 元件分类： | 稳压器 |
| 英文描述： | 4 A SWITCHING REGULATOR, 63 kHz SWITCHING FREQ-MAX, PSSO5 |
| 封装： | GREEN, PLASTIC, TO-263, D2PAK, 5 PIN |
| 文件页数： | 7/29页 |
| 文件大小： | 1019K |
| 代理商： | TL2575HV-05IKTTRG3 |
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Inductor
Output Voltage Ripple and Transients
Feedback Connection
ON/OFF Input
1-A SIMPLE STEP-DOWN SWITCHING VOLTAGE REGULATORS
SLVS638B – MAY 2006 – REVISED JANUARY 2007
APPLICATION INFORMATION (continued)
Proper inductor selection is key to the performance-switching power-supply designs. One important factor to
consider is whether the regulator is used in continuous mode (inductor current flows continuously and never
drops to zero) or in discontinuous mode (inductor current goes to zero during the normal switching cycle). Each
mode has distinctively different operating characteristics and, therefore, can affect the regulator performance
and requirements. In many applications, the continuous mode is the preferred mode of operation, since it offers
greater output power with lower peak currents, and also can result in lower output ripple voltage. The
advantages of continuous mode of operation come at the expense of a larger inductor required to keep inductor
current continuous, especially at low output currents and/or high input voltages.
The TL2575 and TL2575HV can operate in either continuous or discontinuous mode. With heavy load currents,
the inductor current flows continuously and the regulator operates in continuous mode. Under light load, the
inductor fully discharges and the regulator is forced into the discontinuous mode of operation. For light loads
(approximately 200 mA or less), this discontinuous mode of operation is perfectly acceptable and may be
desirable solely to keep the inductor value and size small. Any buck regulator eventually operates in
discontinuous mode when the load current is light enough.
The type of inductor chosen can have advantages and disadvantages. If high performance/quality is a concern,
then more-expensive toroid core inductors are the best choice, as the magnetic flux is contained completely
within the core, resulting in less EMI and noise in nearby sensitive circuits. Inexpensive bobbin core inductors,
however, generate more EMI as the open core does not confine the flux within the core. Multiple switching
regulators located in proximity to each other are particularly susceptible to mutual coupling of magnetic fluxes
from each other’s open cores. In these situations, closed magnetic structures (such as a toroid, pot core, or
E-core) are more appropriate.
Regardless of the type and value of inductor used, the inductor never should carry more than its rated current.
Doing so may cause the inductor to saturate, in which case the inductance quickly drops, and the inductor looks
like a low-value resistor (from the dc resistance of the windings). As a result, switching current rises dramatically
(until limited by the current-by-current limiting feature of the TL2575 and TL2575HV) and can result in
overheating of the inductor and the IC itself. Note that different types of inductors have different saturation
characteristics.
As with any switching power supply, the output of the TL2575 and TL2575HV have a sawtooth ripple voltage at
the switching frequency. Typically about 1% of the output voltage, this ripple is due mainly to the inductor
sawtooth ripple current and the ESR of the output capacitor (see note on COUT). Furthermore, the output also
may contain small voltage spikes at the peaks of the sawtooth waveform. This is due to the fast switching of the
output switch and the parasitic inductance of COUT. These voltage spikes can be minimized through the use of
low-inductance capacitors.
There are several ways to reduce the output ripple voltage: a larger inductor, a larger COUT, or both. Another
method is to use a small LC filter (20
H and 100 F) at the output. This filter can reduce the output ripple
voltage by a factor of 10 (see Figure 2).
For fixed-voltage options, FEEDBACK must be wired to VOUT. For the adjustable version, FEEDBACK must be
connected between the two programming resistors. Again, both of these resistors should be in close proximity to
the regulator, and each should be less than 100 k
to minimize noise pickup.
ON/OFF should be grounded or be a low-level TTL voltage (typically <1.6 V) for normal operation. To shut down
the TL2575 or TL2575HV and put it in standby mode, a high-level TTL or CMOS voltage should be supplied to
this pin. ON/OFF should not be left open and safely can be pulled up to VIN with or without a pullup resistor.
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| TL2575HV-15IKTTRG3 | 4 A SWITCHING REGULATOR, 63 kHz SWITCHING FREQ-MAX, PSSO5 |
| TL2575HV-12IN | 4 A SWITCHING REGULATOR, 63 kHz SWITCHING FREQ-MAX, PDIP16 |
| TL2575HV-33IKV | 4 A SWITCHING REGULATOR, 63 kHz SWITCHING FREQ-MAX, PZFM5 |
| TL2575-33IKTTR | 4 A SWITCHING REGULATOR, 63 kHz SWITCHING FREQ-MAX, PSSO5 |
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相关代理商/技术参数 |
参数描述 |
|---|---|
| TL2575HV-05IKV | 功能描述:直流/直流开关调节器 1-A Step-Down Vltge RoHS:否 制造商:International Rectifier 最大输入电压:21 V 开关频率:1.5 MHz 输出电压:0.5 V to 0.86 V 输出电流:4 A 输出端数量: 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:PQFN 4 x 5 |
| TL2575HV-05IN | 功能描述:直流/直流开关调节器 1-A Step-Down Vltge RoHS:否 制造商:International Rectifier 最大输入电压:21 V 开关频率:1.5 MHz 输出电压:0.5 V to 0.86 V 输出电流:4 A 输出端数量: 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:PQFN 4 x 5 |
| TL2575HV-05INE4 | 功能描述:直流/直流开关调节器 1-A Step-Down Vltge RoHS:否 制造商:International Rectifier 最大输入电压:21 V 开关频率:1.5 MHz 输出电压:0.5 V to 0.86 V 输出电流:4 A 输出端数量: 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:PQFN 4 x 5 |
| TL2575HV-05-Q1 | 制造商:TI 制造商全称:Texas Instruments 功能描述:1-A SIMPLE STEP-DOWN SWITCHING VOLTAGE REGULATORS |
| TL2575HV-05QKTTRQ1 | 功能描述:直流/直流开关调节器 AC 1A Simple St-Down Switching Vltg Reg RoHS:否 制造商:International Rectifier 最大输入电压:21 V 开关频率:1.5 MHz 输出电压:0.5 V to 0.86 V 输出电流:4 A 输出端数量: 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:PQFN 4 x 5 |
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