ZHCSIN0 August   2018 TPS62810-Q1 , TPS62812-Q1

ADVANCE INFORMATION for pre-production products; subject to change without notice.  

  1. 特性
  2. 应用
  3. 说明
    1.     Device Images
      1.      原理图
      2.      效率与输出电流间的关系;VOUT = 3.3V;PWM/PFM;fS = 2.25MHz
  4. 修订历史记录
  5. Device Comparison Table
  6. Pin Configuration and Functions
    1.     Pin Functions
  7. Specifications
    1. 7.1 Absolute Maximum Ratings
    2. 7.2 ESD Ratings
    3. 7.3 Recommended Operating Conditions
    4. 7.4 Thermal Information
    5. 7.5 Electrical Characteristics
    6. 7.6 Typical Characteristics
  8. Parameter Measurement Information
    1. 8.1 Schematic
  9. Detailed Description
    1. 9.1 Overview
    2. 9.2 Functional Block Diagram
    3. 9.3 Feature Description
      1. 9.3.1 Precise Enable
      2. 9.3.2 COMP/FSET
      3. 9.3.3 MODE / SYNC
      4. 9.3.4 Spread Spectrum Clocking (SSC); optional
      5. 9.3.5 Undervoltage Lockout (UVLO)
      6. 9.3.6 Power Good Output (PG)
      7. 9.3.7 Thermal Shutdown
    4. 9.4 Device Functional Modes
      1. 9.4.1 Pulse Width Modulation (PWM) Operation
      2. 9.4.2 Power Save Mode Operation (PWM/PFM)
      3. 9.4.3 100% Duty-Cycle Operation
      4. 9.4.4 Current Limit and Short Circuit Protection
      5. 9.4.5 Fold-back Current Limit and Short Circuit Protection
      6. 9.4.6 Output Discharge
      7. 9.4.7 Soft Start / Tracking (SS/TR)
  10. 10Application and Implementation
    1. 10.1 Application Information
      1. 10.1.1 Programming the Output Voltage
      2. 10.1.2 External Component Selection
      3. 10.1.3 Inductor Selection
      4. 10.1.4 Capacitor Selection
        1. 10.1.4.1 Input Capacitor
        2. 10.1.4.2 Output Capacitor
    2. 10.2 Typical Application
      1. 10.2.1 Design Requirements
      2. 10.2.2 Detailed Design Procedure
      3. 10.2.3 Application Curves
    3. 10.3 System Examples
      1. 10.3.1 Voltage Tracking
  11. 11Power Supply Recommendations
  12. 12Layout
    1. 12.1 Layout Guidelines
    2. 12.2 Layout Example
  13. 13器件和文档支持
    1. 13.1 器件支持
      1. 13.1.1 第三方产品免责声明
    2. 13.2 文档支持
      1. 13.2.1 相关文档
    3. 13.3 相关链接
    4. 13.4 接收文档更新通知
    5. 13.5 社区资源
    6. 13.6 商标
    7. 13.7 静电放电警告
    8. 13.8 术语表
    9. 13.9 勘误
  14. 14机械、封装和可订购信息

封装选项

机械数据 (封装 | 引脚)
  • RWY|9
散热焊盘机械数据 (封装 | 引脚)
订购信息

COMP/FSET

This pin allows to set two different parameters independently:

  • internal compensation settings for the control loop (3 settings available)
  • the switching frequency in PWM mode from 1.8 MHz to 4 MHz

A resistor from COMP/FSET to GND changes the compensation as well as the switching frequency. The change in compensation allows to adopt the device to different values of output capacitance. The resistor should be placed close to the pin to keep the parasitic capacitance on the pin to a minimum. The compensation setting is sampled at start-up of the converter, so a change in the resistor during operation only has an effect on the switching frequency but not on the compensation.

In order to save external components, the pin can also be directly tied to VIN or GND to set a pre-defined switching frequency / compensation. Do not leave the pin floating.

The switching frequency has to be selected based on the input voltage and the output voltage to meet the specifications for the minimum on-time and minimum off-time.

Example: VIN = 5 V, VOUT = 1 V --> duty cycle = 1 V / 5 V = 0.2

  • --> ton,min = 1/fs x 0.2
  • --> fsw,max = 1/ton,min x 0.2 = 1/0.075 ns x 0.2 = 2.67 MHz

The compensation range has to be chosen based on the minimum capacitance used. The capacitance can be increased from the minimum value as given in Table 2 and Table 3, up to the maximum of 470 µF in all of the 3 compensation ranges. If the capacitance of an output changes during operation, e.g. when load switches are used to connect or disconnect parts of the circuitry, the compensation has to be chosen for the minimum capacitance on the output. With large output capacitance, the compensation should be done based on that large capacitance to get the best load transient response. Compensating for large output capacitance but placing less capacitance on the output may lead to instability.

The switching frequency for the different compensation setting is determined by the following equations.

For compensation (comp) setting 1:

Space

Equation 1. TPS62810-Q1 TPS62812-Q1 equation_Comp1a.gif

For compensation (comp) setting 2:

Space

Equation 2. TPS62810-Q1 TPS62812-Q1 equation_Comp2a.gif

Space

For compensation (comp) setting 3:

Space

Equation 3. TPS62810-Q1 TPS62812-Q1 equation_Comp3a.gif

Table 2. Switching Frequency and Compensation for TPS62810 (4 A) and TPS62813 (3 A)

Compensation RCF Switching Frequency Minimum Output
Capacitance
for VOUT < 1 V
Minimum Output
Capacitance
for 1 V ≤ VOUT < 3.3 V
Minimum Output
Capacitance
for VOUT ≥ 3.3 V
for smallest output capacitance
(comp setting 1)
10 kΩ ... 4.5 kΩ 1.8 MHz (10 kΩ) ... 4 MHz (4.5 kΩ)
according to Equation 1
53 µF 32 µF 27 µF
for medium output capacitance
(comp setting 2)
40 kΩ ... 18 kΩ 1.8 MHz (40 kΩ) ... 4 MHz (18 kΩ)
according to Equation 2
100 µF 60 µF 50 µF
for large output capacitance
(comp setting 3)
100 kΩ ... 45 kΩ 1.8 MHz (100 kΩ) ... 4 MHz (45 kΩ)
according to Equation 3
200 µF 120 µF 100 µF
for smallest output capacitance
(comp setting 1)
tied to GND internally fixed 2.25 MHz 53 µF 32 µF 27 µF
for large output capacitance
(comp setting 3)
tied to VIN internally fixed 2.25 MHz 200 µF 120 µF 100 µF

Table 3. Switching Frequency and Compensation for TPS62812 (2 A) and TPS62811 (1 A)

Compensation RCF Switching Frequency Minimum Output Capacitance
for VOUT < 1 V
Minimum Output Capacitance
for 1 V ≤ VOUT < 3.3 V
Minimum Output Capacitance
for VOUT ≥ 3.3 V
for smallest output capacitance
(comp setting 1)
10 kΩ ... 4.5 kΩ 1.8 MHz (10 kΩ) ... 4 MHz (4.5 kΩ)
according to Equation 1
30 µF 18 µF 15 µF
for medium output capacitance
(comp setting 2)
40 kΩ ... 18 kΩ 1.8 MHz (40 kΩ) ... 4 MHz (18 kΩ)
according to Equation 2
60 µF 36 µF 30 µF
for large output capacitance
(comp setting 3)
100 kΩ ... 45 kΩ 1.8MHz (100 kΩ) ...4 MHz (45 kΩ)
according to Equation 3
130 µF 80 µF 68 µF
for smallest output capacitance
(comp setting 1)
tied to GND internally fixed 2.25 MHz 30 µF 18 µF 15 µF
for large output capacitance
(comp setting 3)
tied to VIN internally fixed 2.25 MHz 130 µF 80 µF 68 µF

Refer to Output Capacitor for further details on the output capacitance required depending on the output voltage.

A too high resistor value for RCF is decoded as "tied to VIN", a value below the lowest range as "tied to GND". The minimum output capacitance in Table 2 and Table 3 is for capacitors close to the output of the device. If the capacitance is distributed, a lower compensation setting may be required.