參數(shù)資料
型號: TPS65251RHAT
廠商: TEXAS INSTRUMENTS INC
元件分類: 穩(wěn)壓器
英文描述: SWITCHING REGULATOR, PQCC40
封裝: 6 X 6 MM, GREEN, PLASTIC, VQFN-40
文件頁數(shù): 17/31頁
文件大小: 1827K
代理商: TPS65251RHAT
2
12
M
ps
fc Vo Co
R
g
Vref gm
p ×
×
=
×
SLVSAA4B – JUNE 2010 – REVISED JANUARY 2011
www.ti.com
Compensation
A type-II compensation circuit is adequate for the converter to have a phase margin between 60 and 90 degrees.
The following equations show the procedure of designing a peak current mode control dc/dc converter.
The compensation design takes the following steps:
1. Set up the anticipated cross-over frequency. In this example, the anticipated cross-over frequency (fc) is 65
kHz. The power stage gain (gmPS ) is 10 A/V and the GM amplifier gain (gM ) is 130 A/V.
(21)
2. Place compensation zero at low frequency to boost the phase margin at the crossover frequency. From the
procedures above, the compensation network includes a 20-k
resistor (R12) and a 4700-pF capacitor (C1).
3. An additional pole can be added to attenuate high frequency noise.
From the procedures above, the compensation network includes a 20-k
resistor (R12) and a 4700-pF capacitor
(C14).
3.3-V and 6.5-V LDO Regulators
The following ceramic capacitor (X7R/X5R) should be connected as close as possible to the described pins:
10 F for V7V pin 28
3.3 F for V3V pin 29
Layout Recommendation
Layout is a critical portion of PMIC designs.
Place VOUT, and LX on the top layer and an inner power plane for VIN.
Fit also on the top layer connections for the remaining pins of the PMIC and a large top side area filled with
ground.
The top layer ground area sould be connected to the internal ground layer(s) using vias at the input bypass
capacitor, the output filter cpacitor and directly under the TPS65251 device to provide a thermal path from the
Powerpad land to ground.
The AGND pin should be tied directly to the power pad under the IC and the power pad.
For operation at full rated load, the top side ground area together with the internal ground plane, must provide
adequate heat dissipating area.
There are several signals paths that conduct fast changing currents or voltages that can interact with stray
inductance or parasitic capacitance to generate noise or degrade the power supplies performance. To help
eliminate these problems, the VIN pin should be bypassed to ground with a low ESR ceramic bypass
capacitor with X5R or X7R dielectric. Care should be taken to minimize the loop area formed by the bypass
capacitor connections, the VIN pins, and the ground connections. Since the LX connection is the switching
node, the output inductor should be located close to the LX pins, and the area of the PCB conductor
minimized to prevent excessive capacitive coupling.
The output filter capacitor ground should use the same power ground trace as the VIN input bypass capacitor.
Try to minimize this conductor length while maintaining adequate width.
The compensation should be as close as possible to the COMP pins. The COMP and OSC pins are sensitive
to noise so the components associated to these pins should be located as close as possible to the IC and
routed with minimal lengths of trace.
24
Copyright 2010–2011, Texas Instruments Incorporated
Product Folder Link(s): TPS65251
相關(guān)PDF資料
PDF描述
TPS65251RHAR SWITCHING REGULATOR, PQCC40
TPS65257RHAT 4 A SWITCHING REGULATOR, 2200 kHz SWITCHING FREQ-MAX, PQCC40
TPS65510RGTRG4 1-CHANNEL POWER SUPPLY SUPPORT CKT, PQCC16
TPS65510RGTTG4 1-CHANNEL POWER SUPPLY SUPPORT CKT, PQCC16
TPS65530ARSLR 0.6 A BATTERY CHARGE CONTROLLER, 1650 kHz SWITCHING FREQ-MAX, PQCC48
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
TPS65252EVM 功能描述:電源管理IC開發(fā)工具 TPS65252 Eval Mod RoHS:否 制造商:Maxim Integrated 產(chǎn)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
TPS65252RHDR 功能描述:PMIC 解決方案 4.5-16V Inp w/ 2 BUCK CONVERTER RoHS:否 制造商:Texas Instruments 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:QFN-24 封裝:Reel
TPS65252RHDT 功能描述:PMIC 解決方案 4.5-16V Inp w/ 2 BUCK CONVERTER RoHS:否 制造商:Texas Instruments 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:QFN-24 封裝:Reel
TPS65253EVM 功能描述:電源管理IC開發(fā)工具 TPS65253 Eval Mod RoHS:否 制造商:Maxim Integrated 產(chǎn)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
TPS65253RHDR 功能描述:PMIC 解決方案 4.5V-16Vin/2 Buck Converters RoHS:否 制造商:Texas Instruments 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:QFN-24 封裝:Reel