SLVUDA8 May   2025

 

  1.   1
  2.   Description
  3.   Get Started
  4.   Features
  5.   Applications
  6.   6
  7. 1Evaluation Module Overview
    1. 1.1 Introduction
    2. 1.2 Kit Contents
    3. 1.3 Specification
    4. 1.4 Device Information
  8. 2Hardware
    1. 2.1 Setup
    2. 2.2 Header Information
    3. 2.3 Jumper Information
    4. 2.4 Test Points
  9. 3Implementation Results
    1. 3.1 TPS60800Q1EVM-068 Evaluation Board
  10. 4Hardware Design Files
    1. 4.1 Schematics
    2. 4.2 PCB Layout of the EVM
    3. 4.3 Bill of Materials (BOM)
  11. 5Additional Information
    1. 5.1 Trademarks

3.1 TPS60800Q1EVM-068 Evaluation Board

The layout of a charge pump is very critical. The suggested layout of the evaluation board can be used as a reference to reduce design time. The evaluation board is split into four sections. Each section contains a different application circuit for the device.
  • Simple inverter or inverter with filter and post regulator (for example, for LCD bias)
  • Doubling inverter (VOUT = –2 VIN)
  • Combined doubler, inverter (VOUT1 = –VIN; VOUT2 = 2 VIN)
  • Step-down charge pump (VOUT = 0.5 VIN)

Standard Inverter With Filter and Post Regulator

The following schematic shows the standard inverter with filter and post regulator application. TPS60800-Q1 charge pump is used to generate a negative output voltage, which is filtered using R1, R2, and C4. The output is stabilized by a TLV431 shunt regulator. Resistors R3 and R4 are used to adjust the output voltage. The negative output voltage VO is determined by the resistor network R4/R3 as follows:

VO = –(1 + R4 / R3) × Vref – R4 × I(ref)

where: Vref is typically 1.24V. I(ref) is the reference input current, which is typically about 0.15µA. The resistors R1 and R2 must provide a cathode current |I(KA,min)| ≥ 0.08mA to the TLV431 at minimum VI. Refer to the TLV431x Low-Voltage Adjustable Precision Shunt Regulator data sheet for further information. Capacitors C3, C6, and C8 are not used in this application. Capacitors C3, C6, and C8 can be added if needed.

For further information, refer to the TPS60800-Q1 Unregulated, 200mA, Automotive, Charge Pump Voltage Inverter data sheet.

TPS60800EVM-068 Standard Inverter With Filter and Post Regulator Figure 3-1 Standard Inverter With Filter and Post Regulator

Voltage Doubler, Inverter

The following schematic shows the TPS60800-Q1 in a dual output application. The no load output voltage of VPOS is twice the input voltage. When loaded, the output voltage decreases due to the forward voltage of D1 and D2. Schottky diodes can also be used. This action increases the output voltage under load. VNEG is the inverting output with VNEG = –VIN. Input current is about two times the output current at VPOS plus the output current at VNEG.

For further information, refer to the TPS60800-Q1 Unregulated, 200mA, Automotive, Charge Pump Voltage Inverter data sheet.

TPS60800EVM-068 Voltage Doubler/Inverter Figure 3-2 Voltage Doubler/Inverter

Doubling Inverter

The following schematic shows the configuration of two TPS60800-Q1 devices connected in series to convert a input voltage in the range of 1.8V to 5V to an output voltage in the range of –3.6V to –10V. Capacitors C14, C15, C17, and C18 must have a voltage rating according to the input voltage, the output capacitor must have a voltage rating of at least twice the input voltage.

For further information, refer to the TPS60800-Q1 Unregulated, 200mA, Automotive, Charge Pump Voltage Inverter data sheet.

TPS60800EVM-068 Doubling Inverter Figure 3-3 Doubling Inverter

Step-Down Charge Pump

TPS60800-Q1 can also be used to step down the input voltage by a factor of two. The following schematic shows this configuration. The output current is twice the input current. To operate an inverter in a step-down configuration, simply exchange the GND and the OUT pin of the inverter. The output resistance is typically 5Ω for a 5V to 2.5V conversion.

For further information, refer to the TPS60800-Q1 Unregulated, 200mA, Automotive, Charge Pump Voltage Inverter data sheet.

TPS60800EVM-068 Step-Down Charge Pump Figure 3-4 Step-Down Charge Pump