ZHCSNK8 March   2021 TPS62810M , TPS62811M , TPS62812M , TPS62813M

PRODUCTION DATA  

  1. 1 特性
  2. 2 应用
  3. 3 说明
  4. 4 Revision History
  5. 5 Device Comparison Table
  6. 6 Pin Configuration and Functions
  7. 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. 8 Parameter Measurement Information
    1. 8.1 Schematic
  9. 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)
      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 Foldback 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 Inductor Selection
      3. 10.1.3 Capacitor Selection
        1. 10.1.3.1 Input Capacitor
        2. 10.1.3.2 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
      2. 10.3.2 Synchronizing to an External Clock
  11. 11Power Supply Recommendations
  12. 12Layout
    1. 12.1 Layout Guidelines
    2. 12.2 Layout Example
  13. 13Device and Documentation Support
    1. 13.1 Device Support
      1. 13.1.1 第三方产品免责声明
    2. 13.2 Documentation Support
      1. 13.2.1 Related Documentation
    3. 13.3 接收文档更新通知
    4. 13.4 支持资源
    5. 13.5 Trademarks
    6. 13.6 静电放电警告
    7. 13.7 术语表
  14. 14Mechanical, Packaging, and Orderable Information

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订购信息

9.3.2 COMP/FSET

This pin lets the user set two different parameters independently:

  • Internal compensation settings for the control loop
  • The switching frequency in PWM mode from 1.8 MHz to 4 MHz

A resistor from COMP/FSET to GND changes the compensation and switching frequency. The change in compensation allows the user to adapt the device to different values of output capacitance. The resistor must be placed close to the pin to keep the parasitic capacitance on the pin to a minimum. The compensation setting is sampled when the converter starts up, so a change in the resistor during operation only has an effect on the switching frequency, but not on the compensation.

To save external components, the pin can also be directly tied to VIN or GND to set a pre-defined switching frequency or 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.

For example: VIN = 5 V, VOUT = 1 V --> duty cycle (DC) = 1 V / 5 V = 0.2

  • with ton = DC × T --> ton,min = 1 / fs,max × DC
  • --> fs,max = 1 / ton,min × DC = 1 / 0.075 µs × 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 9-1 and Table 9-2, up to a maximum of 470 µF in all of the three compensation ranges. If the capacitance of an output changes during operation, for example, when load switches are used to connect or disconnect parts of the circuitry, the compensation must be chosen for the minimum capacitance on the output. With large output capacitance, the compensation must 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, can lead to instability.

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

For compensation (comp) setting 1:

Equation 1. GUID-F9728A22-3C0A-460C-9170-AFBD26DA9836-low.gif

For compensation (comp) setting 2:

Equation 2. GUID-793E64BE-6F66-46F8-8F40-1B235B8F69C0-low.gif

For compensation (comp) setting 3:

Equation 3. GUID-77AEB35B-B0AF-47D6-8BA1-CC30DCD6FEF0-low.gif
Table 9-1 Switching Frequency and Compensation for TPS62810M (4 A) and TPS62813M (3 A)
COMPENSATIONRCFSWITCHING FREQUENCYMINIMUM 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 the smallest output capacitance
(comp setting 1)		10 kΩ ... 4.5 kΩ1.8 MHz (10 kΩ) ... 4 MHz (4.5 kΩ)
according to Equation 1		53 µF32 µF27 µF
for medium output capacitance
(comp setting 2)		33 kΩ ... 15 kΩ1.8 MHz (33 kΩ) ... 4 MHz (15 kΩ)
according to Equation 2		100 µF60 µF50 µF
for large output capacitance
(comp setting 3)		100 kΩ ... 45 kΩ1.8 MHz (100 kΩ) ... 4 MHz (45 kΩ)
according to Equation 3		200 µF120 µF100 µF
for the smallest output capacitance
(comp setting 1)		tied to GNDinternally fixed 2.25 MHz53 µF32 µF27 µF
for large output capacitance
(comp setting 3)		tied to VINinternally fixed 2.25 MHz200 µF120 µF100 µF
Table 9-2 Switching Frequency and Compensation for TPS62812M (2 A) and TPS62811M (1 A)
COMPENSATIONRCFSWITCHING FREQUENCYMINIMUM 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 the smallest output capacitance
(comp setting 1)		10 kΩ ... 4.5 kΩ1.8 MHz (10 kΩ) ... 4 MHz (4.5 kΩ)
according to Equation 1		30 µF18 µF15 µF
for medium output capacitance
(comp setting 2)		33 kΩ ... 15 kΩ1.8 MHz (33 kΩ) ... 4 MHz (15 kΩ)
according to Equation 2		60 µF36 µF30 µF
for large output capacitance
(comp setting 3)		100 kΩ ... 45 kΩ1.8MHz (100 kΩ) ...4 MHz (45 kΩ)
according to Equation 3		130 µF80 µF68 µF
for the smallest output capacitance
(comp setting 1)		tied to GNDinternally fixed 2.25 MHz30 µF18 µF15 µF
for large output capacitance
(comp setting 3)		tied to VINinternally fixed 2.25 MHz130 µF80 µF68 µF

Refer to Section 10.1.3.2 for further details on the required 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 is decoded as "tied to GND". The minimum output capacitance in Table 9-1 and Table 9-2 is for capacitors close to the output of the device. If the capacitance is distributed, a lower compensation setting can be required. All values are effective capacitance including, but not limited to:

  • All tolerances
  • Aging
  • DC bias effect