SNVAA98 January   2024 LM25148 , LM74910-Q1 , TPS38700 , TPS389006 , TPS389006-Q1 , TPS628301 , TPS628302 , TPS628303 , TPS6287B10 , TPS6287B25 , TPS746

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1 Introduction
  5. 2 Design Parameters
  6. 3 Schematics
  7. 4 Design Considerations
  8. 5 Front-End Protection
  9. 6 3.3V Always-ON Bias Supply
  10. 7 5V Pre-Regulator Buck Converter
  11. 8 Low-Voltage High-Current Core Rail Buck Converter
  12. 9 On-Board Core Rail Output Load Transient Stepper
  13. 10Multiple Peripheral Rail Buck Converters Sub-Circuits Schematic
  14. 11Voltage Supervisor and Sequencer
  15. 1212-Channel Sequencer Alternative
  16. 13Summary
  17. 14References

11 Voltage Supervisor and Sequencer

TPS389006 is a programmable 6-channel voltage supervisor. The RS_1/2 is a remote ground sense pin that can be connected to the local ground terminal of either the MON1 or MON2 voltage rails. This type of ground sensing provides a precision, differential voltage sensing of that rail. If the RS_1/2 pin is not used, all six voltage sense lines can share the same common ground. This device contains numerous registers that can be programmed via I2C. Programmable parameters include, voltage threshold levels, hysteresis levels, and glitch immunity times. The IRQ/ pin output can be used as a system Power Good. The device I2C address can be programmed using a resistor from the ADDR pin to GND. With the 5.36 k resistor depicted in the schematic, the address is programmed to 0x30.

The TPS389006 used in Figure 3-7 depicts the adjustable variant of the device, which can require a resistor voltage divider at the input of each sense line to adjust the voltage threshold. If the design does not permit the use of resistor voltage dividers, please use these devices for evaluation purposes, then contact a TI representative to discuss a one-time programmable (OTP) variant, to set the required thresholds as default for each sense pin.

The TPS38700S is a 6-channel sequencer IC used to turn each regulator ON and OFF in a particular sequence with programmable delays between each event. Both the TPS389006 voltage supervisor and TPS38700S sequencer can either be used independently or in tandem with one another. In this design example, the two ICs are implemented to be used together. In this configuration, when the devices are enabled, their ACT pins go HIGH, enabling the first regulator in the system. When the measured voltage of this first rail is within the programmed power good voltage window, the supervisor communicates a toggle signal to the sequencer. Once this signal is received, the sequencer can set HIGH the next enable signal in the sequence, after the programmed delay time elapses. This continues to take place until all sequences are enabled and all six regulators are enabled. When the sequence is disabled, the same operation takes place, except this time in the opposite order.