TPS6302X

Part: TPS63020, TPS63021 from Texas Instruments

Type: High Efficiency Single Inductor Buck-boost Converter

Description: The TPS6302x is a 1.8–5.5 V input, 3 A output current (for VIN > 2.5 V, VOUT = 3.3 V) synchronous buck-boost converter with 4 A switches, 2.4 MHz fixed frequency operation, and high efficiency over the entire load range.

Operating Conditions:

• Supply voltage: 1.8–5.5 V
• Operating free air temperature: -40 to 85 °C
• Operating junction temperature: -40 to 125 °C
• Output voltage range: 1.2–5.5 V (adjustable for TPS63020)

Absolute Maximum Ratings:

• Max supply voltage: 7 V (VIN, VINA, VOUT, PS/SYNC, EN, FB, PG)
• Max continuous current: 4000 mA (Average switch current limit)
• Max junction/storage temperature: 150 °C

Key Specs:

• Input voltage range: 1.8–5.5 V
• TPS63020 output voltage range: 1.2–5.5 V
• TPS63021 output voltage: 3.3 V (typical)
• Oscillator frequency: 2200–2600 kHz (2400 kHz typical)
• Average switch current limit: 3500 mA (min) to 4500 mA (max) at VIN = VINA = 3.6 V, TA = 25°C
• High side switch on resistance: 50 mΩ (typical) at VIN = VINA = 3.6 V
• Low side switch on resistance: 50 mΩ (typical) at VIN = VINA = 3.6 V
• Operating quiescent current: 25 μA (typical) for VIN and VINA
• Overtemperature protection: 140 °C (typical)

Features:

• High efficiency over the entire load range
• Operating quiescent current: 25 μA
• Average current mode buck-boost architecture
• Automatic transition between buck, boost, and buck-boost modes
• Fixed frequency operation at 2.4 MHz, with synchronization possible
• Power good output
• Overtemperature and overvoltage protection
• Load disconnect during shutdown

Applications:

• Pre-regulation in battery-powered devices (e.g., portable data terminals, barcode scanners, e-cigarettes)
• Voltage stabilizer (e.g., wired/wireless communication, PLC, optical modules)
• Backup supercapacitor supply (e.g., electricity meters, SSDs)

Package:

• VSON (14) (DSJ)

¹• Input voltage range: 1.8 V to 5.5 V

• Adjustable output voltage: 1.2 V to 5.5 V

• Output current for VIN > 2.5 V, VOUT = 3.3 V: 2 A

• High efficiency over the entire load range

– Operating quiescent current: 25 μA

– Power save mode with mode selection

• Average current mode buck-boost architecture

– Automatic transition between modes

– Fixed frequency operation at 2.4 MHz

– Synchronization possible

• Power good output

• Safety and robust operation features

– Overtemperature, overvoltage protection

– Load disconnect during shutdown

• Create a custom design using the

– TPS63020 with WEBENCH Power Designer

– TPS63021 with WEBENCH Power Designer

• Pre-regulation in battery-powered devices: EPOS (portable data terminal, barcode scanner), ecigarette, single board computer, IP network camera, video doorbell, land mobile radios
• • Voltage stabilizer: wired communication, wireless communication, PLC, optical module
• • Backup supercapacitor supply: electricity meter, solid state drive (SSD) - enterprise

DSJ Package 14-Pin VSON with Exposed Thermal Pad Top View

Pin Functions

over recommended free-air temperature range and over recommended input voltage range (typical at an ambient temperature range of 25°C) (unless otherwise noted)

Product Folder Links: TPS63020 TPS63021

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VOUT = 3.3V

6.6 Typical Characteristics

over operating free-air temperature range (unless otherwise noted)(1)

⁽¹⁾ Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated under Recommended Operating Conditions is not implied. Exposure to absolute-maximum-rated conditions for extended periods my affect device reliability.

⁽¹⁾ For more information about traditional and new thermal metrics, see the Semiconductor and IC Package Thermal Metrics application report.

⁽²⁾ All voltages are with respect to network ground terminal.

⁽³⁾ Normal switching operation

⁽²⁾ JEDEC document JEP157 states that, with basic ESD control methods applied, 250 V CDM allows a safe manufacturing.

The TPS6302x are high efficiency, low quiescent current, non-inverting buck-boost converters suitable for applications that need a regulated output voltage from an input supply that can be higher, lower, or equal to the output voltage. Output currents can go as high as 2 A in boost mode and as high as 4 A in buck mode. The average current in the switches is limited to a typical value of 4 A.

8.2 Typical Application

Figure 7. Application Circuit

8.2.1 Design Requirements

The design guideline provides a component selection to operate the device within the recommended operating conditions. See Table 1 for possible inductor and capacitor combinations.

For the fixed output voltage option, the feedback pin needs to be connected to the VOUT pin.

Table 1. Matrix of Output Capacitor and Inductor Combinations

• NOMINAL NOMINAL OUTPUT CAPACITOR VALUE μF

• INDUCTOR VALUE
  μH 2×22 3×22 4×22 ≥ 100

• 1.0 + + +

• 1.5 + (3)
  + + +

• 2.2 + +

• (1) Inductor tolerance and current derating is anticipated. The effective inductance can vary by 20% and –30%.

• (2) Capacitance tolerance and DC bias voltage derating is anticipated. The effective capacitance can vary by 20% and –50%.

(3) Typical application. Other check marks indicate possible filter combinations.

8.2.2 Detailed Design Procedure

The TPS6302x series of buck-boost converter has internal loop compensation. Therefore, the external inductor and output capacitors have to be selected to work with the internal compensation. When selecting the external components, a low limit for the inductor value exists to avoid subharmonic oscillation which can be caused by a far too fast ramp up of the inductor current. For the TPS6302x series, the inductor value must be kept at or above 1 μH.

In particular, either 1 μH or 1.5 μH is recommended working at an output current between 1.5 A and 2 A. If operating with a lower load current, it is also possible to use 2.2 μH.

Selecting a larger output capacitor value is less critical because the corner frequency moves to lower frequencies.

8.2.2.1 Custom Design with WEBENCH Tools

Click here to create a custom design using the TPS63020 device with the WEBENCH® Power Designer.

• 1. Start by entering your V_IN, V_OUT and I_OUT requirements.
• 1. Optimize your design for key parameters like efficiency, footprint or cost using the optimizer dial and compare this design with other possible solutions from Texas Instruments.
• WEBENCH Power Designer provides you with a customized schematic along with a list of materials with real time pricing and component availability.
• 1. In most cases, you will also be able to:
  • Run electrical simulations to see important waveforms and circuit performance.
  • Run thermal simulations to understand the thermal performance of your board,
  • Export your customized schematic and layout into popular CAD formats,
  • Print PDF reports for the design, and share your design with colleagues.
• 1. Get more information about WEBENCH tools at www.ti.com/webench.

8.2.2.2 Inductor Selection

The inductor selection is affected by several parameters such as the following:

• Inductor ripple current
• Output voltage ripple
• Transition point into Power Save Mode
• Efficiency

See Table 2 for a list of typical inductors.

For high efficiencies, the inductor must have a low DC resistance to minimize conduction losses. Especially at high-switching frequencies, the core material has a high impact on efficiency. When using small chip inductors, the efficiency is reduced mainly due to higher inductor core losses. This needs to be considered when selecting the appropriate inductor. The inductor value determines the inductor ripple current. The larger the inductor value, the smaller the inductor ripple current and the lower the conduction losses of the converter. Conversely, larger inductor values cause a slower load transient response. Use Equation 2 to avoid saturation of the inductor when calculating the peak current for the inductor in steady state operation. Only the equation which defines the switch current in boost mode is shown because this provides the highest value of current and represents the critical current value for selecting the right inductor.

Duty Cycle Boost $D = frac{V_OUT - V_IN}{V_OUT}$

$I_PEAK = frac{Iout}{eta × (1 - D)} + frac{Vin × D}{2 × f × L}$ (1)

where

• D = duty cycle in boost mode
• f = converter switching frequency (typical 2.5 MHz)
• L = inductor value
• $\eta= estimated converter efficiency (use the number from the efficiency curves or 0.9 as an assumption)

(2)

NOTE

The calculation must be done for the minimum input voltage in boost mode.

Calculating the maximum inductor current using the actual operating conditions gives the minimum saturation current of the inductor needed. It is recommended to choose an inductor with a saturation current 20% higher than the value calculated using Equation 2. Table 2 lists the possible inductors.

Table 2. List of Recommended Inductors (1)

• INDUCTOR
  VALUE [μH] SATURATION
  CURRENT [A] DCR [mΩ] PART NUMBER MANUFACTURER SIZE (LxWxH
  mm)
• 1.5 5.1 15 XFL4020-152ME Coilcraft 4 x 4 x 2.1
• 1.5 5.4 24 FDV0530S-H-1R5M muRata 5 x 5 x 3

(1) See Third-party Products Disclaimer.

8.2.2.3 Output Capacitor Selection

For the output capacitor, it is recommended to use of small ceramic capacitors placed as close as possible to the VOUT and PGND pins of the IC. The recommended nominal output capacitors are three times 22 μF. If, for any reason, the application requires the use of large capacitors that cannot be placed close to the IC, use a smaller ceramic capacitor in parallel to the large capacitor. Place the small capacitor as close as possible to the VOUT and PGND pins of the IC.

There are no additional requirements regarding minimum ESR. There is also no upper limit for the output capacitance value. Larger capacitors cause lower output voltage ripple as well as lower output voltage drop during load transients.

8.2.2.4 Input Capacitor Selection

A 10 μF input capacitor is recommended to improve line transient behavior of the regulator and EMI behavior of the total power supply circuit. An X5R or X7R ceramic capacitor placed as close as possible to the VIN and PGND pins of the IC is recommended. This capacitance can be increased without limit. If the input supply is located more than a few inches from the TPS6302x converter, additional bulk capacitance can be required in addition to the ceramic bypass capacitors. An electrolytic or tantalum capacitor with a value of 47 μF is a typical choice.

8.2.2.5 Bypass Capacitor

To make sure that the internal control circuits are supplied with a stable low noise supply voltage, a capacitor can be connected between VINA and GND. Using a ceramic capacitor with a value of 0.1 μF is recommended. The value of this capacitor must not be higher than 0.22 μF.

8.2.3 Setting The Output Voltage

When the adjustable output voltage version TPS63020 is used, the output voltage is set by an external resistor divider. The resistor divider must be connected between VOUT, FB, and GND. The feedback voltage is 500 mV nominal. The low-side resistor R2 (between FB and GND) must be kept in the range of 200 kΩ. Use Equation 3 to calculate the high-side resistor R1 (between VOUT and FB).R1 = R2 × ≤ft(frac{V_OUT}{V_FB} - 1right)$

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where

• $V_FB = 500 mV$ (3)

Table 3. Resistor Selection For Typical Output Voltages

Table 3. Resistor Selection For Typical Output Voltages (continued)

8.2.4 Application Curves

Table 4. Components for Application Characteristic Curves for VOUT = 3.3 V (1)(2)

⁽¹⁾ See Third-Party Products Discalimer.

Product Folder Links: TPS63020 TPS63021

16

⁽²⁾ For other output voltages, refer to Table 3 for resistor values.

Table 5. Typical Characteristics Curves

• PARAMETER CONDITIONS FIGURE
• EFFICIENCY
• Efficiency vs Output Current, TPS63020 (Power save mode
  enabled) VIN = 1.8 V, 2.4 V, 3.6 V, VOUT = 2.5 V, 4.5 V,
  PS/SYNC = Low Figure 8
• Efficiency vs Output Current, TPS63020 (PWM only) VIN = 1.8 V, 2.4 V, 3.6 V, VOUT = 2.5 V, 4.5 V,
  PS/SYNC = High Figure 9
• Efficiency vs Output Current, TPS63021 (Power save mode
  enabled) VIN = 2.4 V, 3.6 V, VOUT = 3.3 V, PS/SYNC =
  Low Figure 10
• Efficiency vs Output Current, TPS63021 (PWM only) VIN = 2.4 V, 3.6 V, VOUT = 3.3 V, PS/SYNC =
  High Figure 11
• Efficiency vs Input Voltage, TPS63020 (Power save mode
  enabled) VOUT = 2.5 V, Load = 10 mA, 500 mA, 1 A, 2 A,
  PS/SYNC = Low Figure 12
• Efficiency vs Input Voltage, TPS63020 (Power save mode
  enabled) VOUT = 4.5 V, Load = 10 mA, 500 mA, 1 A, 2 A,
  PS/SYNC = Low Figure 13
• Efficiency vs Input Voltage, TPS63020 (PWM only) VOUT = 2.5 V, Load = 10 mA, 500 mA, 1 A, 2 A,
  PS/SYNC = Low Figure 14
• Efficiency vs Input Voltage, TPS63020 (PWM only) VOUT = 2.5 V, Load = 10 mA, 500 mA, 1 A, 2 A,
  PS/SYNC = Low Figure 15
• Efficiency vs Input Voltage, TPS63021 (Power save mode
  enabled) VOUT = 3.3 V, Load = 10 mA, 500 mA, 1 A, 2 A,
  PS/SYNC = Low Figure 16
• Efficiency vs Input Voltage, TPS63021 (PWM only) VOUT = 3.3 V, Load = 10 mA, 500 mA, 1 A, 2 A,
  PS/SYNC = Low Figure 17
• REGULATION ACCURACY
• Load Regulation, PWM Boost Operation, TPS63020 VIN = 3.6 V , VOUT = 4.5 V, PS/SYNC = High Figure 18
• Load Regulation, PWM Buck Operation, TPS63020 VIN = 3.6 V, VOUT = 2.5 V, PS/SYNC = High Figure 19
• Load Regulation, PWM Operation, TPS63021 VIN = 3.6 V, VOUT = 3.3 V, PS/SYNC = High Figure 20
• Load Transient, TPS63021 VIN = 2.4 V, VOUT = 3.3 V, Load = 500 mA to
  1.5 A Figure 21
• Load Transient, TPS63021 VIN = 4.2 V, VOUT = 3.3 V, Load = 500 mA to 1.5
  A Figure 22
• Line Transient, TPS63021 VIN = 3.0 V to 3.7 V, VOUT = 3.3 V, Load = 1.5 A Figure 23
• START-UP
• Start-up Behavior from Rising Enable, TPS63021 VIN = 2.4 V, VOUT = 3.3 V, Load = 2.2 Ω Figure 24
• Start-up Behavior from Rising Enable, TPS63021 VIN = 4.2 V, VOUT = 3.3 V, Load = 2.2 Ω Figure 25
• Start-up Behavior from Rising Enable, TPS63021 VIN = 2.4 V, VOUT = 3.3 V, Load = 2.2 Ω Figure 26
• Start-up Behavior from Rising Enable, TPS63021 VIN = 4.2 V, VOUT = 3.3 V, Load = 2.2 Ω Figure 27

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