TIDUFC2 April   2025

 

  1.   1
  2.   Description
  3.   Resources
  4.   Features
  5.   Applications
  6.   6
  7. 1System Description
    1. 1.1 Key System Specifications
  8. 2System Overview
    1. 2.1 Block Diagram
    2. 2.2 Design Considerations
      1. 2.2.1 High-Voltage Generator Circuit
      2. 2.2.2 Low-Voltage Switching Mode Power Supply
      3. 2.2.3 Sitara™ MCU AM2431 Reset and Power Rail Monitoring Circuit
      4. 2.2.4 Clock Generator
      5. 2.2.5 CMOS to LVDS Driver
      6. 2.2.6 Layout Guidance
    3. 2.3 Highlighted Products
      1. 2.3.1 TX7516
      2. 2.3.2 TMU9832
      3. 2.3.3 AM2431
  9. 3Hardware, Software, Testing Requirements, and Test Results
    1. 3.1 Hardware Requirements
      1. 3.1.1 TIDA-010256 PCB Overview
      2. 3.1.2 TIDA-010256 Connector Settings
    2. 3.2 Software Requirements
    3. 3.3 Test Setup
    4. 3.4 Test Results
      1. 3.4.1 High-Voltage Power Supply Output Ripple
      2. 3.4.2 Output Waveform
      3. 3.4.3 Thermal Test
  10. 4Design and Documentation Support
    1. 4.1 Design Files
      1. 4.1.1 Schematics
      2. 4.1.2 BOM
    2. 4.2 Tools and Software
    3. 4.3 Documentation Support
    4. 4.4 Support Resources
    5. 4.5 Trademarks

2.2.2 Low-Voltage Switching Mode Power Supply

The TPSM63603 synchronous buck power module is a highly integrated 36V, 3A, DC/DC device that combines power MOSFETs, a shielded inductor, and passives in an Enhanced HotRod™ QFN package. The module has pins for VIN and VOUT located at the corners of the package for optimized input and output capacitor layout placement. Four larger thermal pads beneath the module enable a simple layout and easy handling in manufacturing.

TPSM63603 module design can be done quickly based on WEBENCH® circuit design and selection simulation services with corresponding input parameters shown in Table 2-2.

Table 2-2 WEBENCH® Simulation Parameters of 5.5V Power Rail
PARAMETERSTYPICAL VALUEWEBENCH INPUT
DC input 12VVinmin = 11.7V, Vmax = 12V
Output voltage +5.5V5.5V
Output voltage rippleAs low as possible±5%
Output current 3A3A
Maximum ambient–40°C to 105°C30°C
External sync frequency Yes500kHz
Set En_Sync pin to with UVLO N/AYes
Table 2-3 WEBENCH® Simulation Parameters of 3.3V Power Rail
PARAMETERSTYPICAL VALUEWEBENCH INPUT
DC input 12VVinmin = 11.7V, Vmax = 12V
Output voltage +3.3V3.3V
Output voltage rippleAs low as possible ±5%
Output current 3A3A
Maximum ambient–40°C to 105°C30°C
External sync frequency Yes500kHz
Set En_Sync pin to with UVLO N/AYes

Figure 2-5 and Figure 2-6 show the schematic resulting from WEBENCH for 5.5V and 3.3V, respectively.


TIDA-010256 Positive 5.5V Power Rail Schematic

Figure 2-5 Positive 5.5V Power Rail Schematic

TIDA-010256 Positive 3.3V Power Rail Schematic

Figure 2-6 Positive 3.3V Power Rail Schematic

Figure 2-7 through Figure 2-10 show the efficiency and output voltage peak-to-peak graphs.


TIDA-010256 Efficiency of 12V to 5.5V

Figure 2-7 Efficiency of 12V to 5.5V

TIDA-010256 Efficiency of 12V to 3.3V

Figure 2-9 Efficiency of 12V to 3.3V

TIDA-010256 Vp-p Noise of 12V to 5.5V

Figure 2-8 Vp-p Noise of 12V to 5.5V

TIDA-010256 Vp-p Noise of 12V to 3.3V

Figure 2-10 Vp-p Noise of 12V to 3.3V

The –5.5V output can be designed to the same parameters but needs to be configured as an inverting Buck according to the inverting buck-boost regulator with a –5V output section of the TPSM63603 High-Density, 3V to 36V Input, 1V to 16V Output, 3A Power Module With Enhanced HotRod™ QFN Package data sheet. Since the switching mode power supply circuits in the ultrasound equipment all require synchronization of the switching frequency, an additional synchronization clock input is required and the –5.5V synchronization signal requires the input level shift. See also the Working With Inverting Buck-Boost Converters application note.

The DC/DC output goes to the TPS74001 and TPS733031 LDO devices which help to lower the noise of the analog power supply. The TPS7A94 is an ultra-low-noise (0.46μVRMS), low dropout (LDO) voltage regulator capable of sourcing 1A with only 150mV of dropout and the TPS7A3301 output noise can be lowered to 16μVRMS.


TIDA-010256 Positive 5V Schematic

Figure 2-11 Positive 5V Schematic

TIDA-010256 Negative 5V Schematic

Figure 2-12 Negative 5V Schematic