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參數資料
| 型號： | TPS62221DDC |
| 廠商： | Texas Instruments, Inc. |
| 英文描述： | 400-mA, 1.25-MHz, HIGH-EFFICIENCY, STEP-DOWN CONVERTER IN THIN-SOT23 |
| 中文描述： | 400毫安，1.25 MHz的，高效率，降壓型轉換器薄，SOT23封裝 |
| 文件頁數： | 13/20頁 |
| 文件大小： | 464K |
| 代理商： | TPS62221DDC |
www.ti.com
APPLICATION INFORMATION
OUTPUT FILTER DESIGN (INDUCTOR AND OUTPUT CAPACITOR)
The TPS6222x series of step-down converter has internal loop compensation. Therefore, the external L-C filter
has to be selected to work with the internal compensation. This is especially important for the fixed output
voltage version. The adjustable output voltage version allows external capacitors across the feedback divider
resistors. This allows higher flexibility of the output filter seletion when using the adjustable output voltage device
TPS62220.
Fixed Ouput Voltage Version
c
1
L
2
CO
1
2
10 H
10 F
15.9 kHz
with L = 10
μ
H, C
O
= 10
μ
F
Adjustable Output Voltage Version
Vout
0.5 V
1
R1
R2
C1
1
2
Z
R1
1
2
22 kHz
R1
TPS62220, TPS62221, TPS62222
TPS62223, TPS62224
TPS62228, TPS62229
SLVS491C–SEPTEMBER 2003–REVISED SEPTEMBER 2004
The internal compensation is optimized to operate with an output filter of L = 10 μH and C
O
= 10 μF. Such an
output filter has its corner frequency at:
As a general rule of thumb, the product L
×
C should not move over a wide range when selecting a different output
filter. This is because the internal compensation is designed to work with a certain output filter corner frequency
as calculated above. This is especially important when selecting smaller inductor or capacitor values that move
the corner frequency to higher frequencies. However, when selecting the output filter a low limit for the inductor
value exists due to other internal circuit limitations. For the TPS6222x series the minimum inductor value should
be kept at 4.7μH. Selecting a larger output capacitor value is less critical because the corner frequency moves to
lower frequencies causing fewer stability problems. The possible output filter combinations are listed in Table 1:
Table 1. Output Filter Combinations for Fixed Output Voltage Versions
V
O
≤
2 V
≤
2 V
≤
2 V
≥
2 V
L
C
O
4.7 μH
6.8 μH
10 μH
10 μH
≥
22 μF (ceramic capacitor)
≥
22 μF (ceramic capacitor)
≥
10 μF (ceramic capacitor)
10 μF (ceramic capacitor)
When the adjustable output voltage version TPS62220 is used, the output voltage is set by the external resistor
divider. See Figure 15.
The output voltage is calculated as
with R1 + R2
≤
1 M
and internal reference voltage V(ref)typ = 0.5 V
R1 + R2 should not be greater than 1 M
for reasons of stability. To keep the operating quiescent current to a
minimum, the feedback resistor divider should have high impedance with R1 + R2
≤
1 M
. In general, for the
adjustable output voltage version, the same stability considerations are valid as for the fixed output voltage
version. Because the adjustable output voltage version uses an external feedback divider, it is possible to adjust
the loop gain using external capacitors across the feedback resistors. This allows a wider selection of possible
output filter components. This is shown in Figure 16. R1 and C1 places a zero in the loop and R2 and C2 places
a pole in the loop. The zero is calculated as:
with R1 = upper resistor of voltage divider, C1 = upper capacitor of voltage divider
13
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| TPS62222DDC | 400-mA, 1.25-MHz, HIGH-EFFICIENCY, STEP-DOWN CONVERTER IN THIN-SOT23 |
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| TPS62223DDC | 400-mA, 1.25-MHz, HIGH-EFFICIENCY, STEP-DOWN CONVERTER IN THIN-SOT23 |
| TPS6222 | 400-mA, 1.25-MHz, HIGH-EFFICIENCY, STEP-DOWN CONVERTER IN THIN-SOT23 |
| TPS62228DDC | 400-mA, 1.25-MHz, HIGH-EFFICIENCY, STEP-DOWN CONVERTER IN THIN-SOT23 |
相關代理商/技術參數 |
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|---|---|
| TPS62221DDCR | 功能描述:直流/直流開關調節器 1.5V Out 400mA Step-Down Converter RoHS:否 制造商:International Rectifier 最大輸入電壓:21 V 開關頻率:1.5 MHz 輸出電壓:0.5 V to 0.86 V 輸出電流:4 A 輸出端數量: 最大工作溫度: 安裝風格:SMD/SMT 封裝 / 箱體:PQFN 4 x 5 |
| TPS62221DDCRG4 | 功能描述:直流/直流開關調節器 1.5V Out 400mA Step-Down Converter RoHS:否 制造商:International Rectifier 最大輸入電壓:21 V 開關頻率:1.5 MHz 輸出電壓:0.5 V to 0.86 V 輸出電流:4 A 輸出端數量: 最大工作溫度: 安裝風格:SMD/SMT 封裝 / 箱體:PQFN 4 x 5 |
| TPS62221DDCT | 功能描述:直流/直流開關調節器 1.5V Out 400mA Step-Down Converter RoHS:否 制造商:International Rectifier 最大輸入電壓:21 V 開關頻率:1.5 MHz 輸出電壓:0.5 V to 0.86 V 輸出電流:4 A 輸出端數量: 最大工作溫度: 安裝風格:SMD/SMT 封裝 / 箱體:PQFN 4 x 5 |
| TPS62221DDCTG4 | 功能描述:直流/直流開關調節器 1.5V Out 400mA Step-Down Converter RoHS:否 制造商:International Rectifier 最大輸入電壓:21 V 開關頻率:1.5 MHz 輸出電壓:0.5 V to 0.86 V 輸出電流:4 A 輸出端數量: 最大工作溫度: 安裝風格:SMD/SMT 封裝 / 箱體:PQFN 4 x 5 |
| TPS62221EVM-014 | 功能描述:電源管理IC開發工具 TPS62221-014 Eval Mod RoHS:否 制造商:Maxim Integrated 產品:Evaluation Kits 類型:Battery Management 工具用于評估:MAX17710GB 輸入電壓: 輸出電壓:1.8 V |
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