High-Precision Thin-Film Resistor Divider with TVS
Industrial Power Rail Monitor
Aperçu
A robust power rail monitoring circuit utilizing the TPS3703 designed for industrial automation, featuring direct hardware shutdown integration and adjustable voltage thresholds.
Hector HectorArchitecture système
POWER
SENSOR
MODULE
ACTUATOR
- POWER_STEP_DOWN → TPS3703_MONITORPowerSupplies stable operating voltage to the TPS3703 supervisor
- VOLTAGE_SENSING_DIVIDER → TPS3703_MONITORADCFeeds filtered scaled DC bus voltage into the TPS3703 SENSE pin
- TPS3703_MONITOR → HARDWARE_SHUTDOWN_LOGICGPIODrives active-low fault signal directly into hardware enable shutdown path
Nomenclature
| Référence | Type | Composant | Fabricant | Boîtier | Qté | Fiche technique | Correspondance |
|---|---|---|---|---|---|---|---|
| LM5164DDAR | POWER | Texas Instruments LM5164 High-Voltage Buck Regulator Steps down high-voltage DC bus to stable low-voltage rail for supervisor logic | Texas Instruments | 8-PowerSOIC (0.154", 3.90mm Width) | 1 | Correspondant | |
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| MPMA1002AT5 | SENSOR | High-Precision Thin-Film Resistor Divider with TVS Scales down the high-voltage DC bus to match the TPS3703 SENSE pin input voltage range | VISHAY | SOT-23 | 1 | Correspondant | |
| TPS3703-33DR | MODULE | Texas Instruments TPS3703 High-Accuracy Window Supervisor Monitors the scaled DC bus voltage against tight over-voltage and under-voltage thresholds | TI | SOP-8 | 1 | Correspondant | |
Afficher les 5 alternatives étudiéesprojects.detail.aiVerified | |||||||
| SN74LVC1G07 | ACTUATOR | Direct Hardware Enable Line Interlock Routes open-drain RESET output directly to system and power supply enable pins | Texas Instruments | — | 1 | Correspondant | |
Afficher les 1 alternatives étudiéesprojects.detail.aiVerified | |||||||
Guide de fabrication
4-6 hoursAdvanced
1
Procurement & Preparation
- Procure all required Bill of Materials components including LM5164DDAR regulator, MPMA1002AT5 thin-film resistor divider, TPS3703-33DR window supervisor, and SN74LVC1G07 buffer for hardware interlock.
- Inspect the printed circuit board (PCB) gerber files and stencil for the power rail monitoring circuit, ensuring proper thermal reliefs on the LM5164 power pad and Kelvin connections for the high-precision resistor divider.
2
Hardware Assembly & Wiring
- Apply Type 4 SAC305 solder paste to the PCB pads using a stainless steel stencil, then position the Texas Instruments LM5164 High-Voltage Buck Regulator and associated passives onto the footprint.
- Mount the High-Precision Thin-Film Resistor Divider with TVS (MPMA1002AT5) and the Texas Instruments TPS3703 High-Accuracy Window Supervisor (TPS3703-33DR) onto their respective pads.
- Integrate the Direct Hardware Enable Line Interlock by placing the SN74LVC1G07 open-drain buffer, routing the open-drain RESET output from the TPS3703 supervisor to the system shutdown pins.
3
Firmware Setup
- Verify hardware logic levels and pull-up resistor values on the RESETn line connected to the SN74LVC1G07 buffer to ensure reliable propagation delay during a fault condition.
4
Testing & Calibration
- Power the circuit using a programmable DC power supply on the high-voltage DC bus input, and verify the LM5164 steps down the voltage to a stable 3V3 rail for the TPS3703 supervisor logic.
- Perform voltage sweep testing on the high-voltage input while monitoring the SENSE pin via the MPMA1002AT5 divider and observing the RESETn output state on an oscilloscope.
Document
Industrial Power Rail Monitor
A robust power rail monitoring circuit utilizing the TPS3703 designed for industrial automation, featuring direct hardware shutdown integration and adjustable voltage thresholds.
Design Overview
| Item | Details |
|---|---|
| Product Type | Power Rail Monitoring Circuit |
| Key Functions | High-voltage DC bus power rail voltage monitoring using TPS3703, Standalone hardware shutdown via direct connection to enable pins, Adjustable thresholds and filtering for industrial automation environments |
| Power Source | High-voltage DC bus step-down converter |
| Connectivity | |
| Size | Standard PCB footprint with moderate component spacing |
| Environment | Industrial automation and harsh environments |
| Difficulty | Advanced |
| Est. Time | 4-6 hours |
System Architecture
Power Topology: High-voltage DC bus steps down via LM5164 to generate a clean 3.3V power rail for the TPS3703 supervisor and associated pull-up circuitry.
Module List
| Module ID | Type | Name | Function | Voltage |
|---|---|---|---|---|
| POWER_STEP_DOWN | POWER | Texas Instruments LM5164 High-Voltage Buck Regulator | Steps down high-voltage DC bus to stable low-voltage rail for supervisor logic | 24V to 3.3V |
| VOLTAGE_SENSING_DIVIDER | SENSOR | High-Precision Thin-Film Resistor Divider with TVS | Scales down the high-voltage DC bus to match the TPS3703 SENSE pin input voltage range | HV_BUS |
| TPS3703_MONITOR | MODULE | Texas Instruments TPS3703 High-Accuracy Window Supervisor | Monitors the scaled DC bus voltage against tight over-voltage and under-voltage thresholds | 3.3V |
| HARDWARE_SHUTDOWN_LOGIC | ACTUATOR | Direct Hardware Enable Line Interlock | Routes open-drain RESET output directly to system and power supply enable pins | 3.3V |
Design Schemes
Analog Direct Hardware Shutdown Scheme ★
Utilizes the TPS3703 precision voltage detector powered via a high-voltage step-down converter, featuring resistive divider threshold configuration, heavy RC filtering for harsh industrial noise rejection, and a direct hardwired connection to downstream converter enable pins for instantaneous fault mitigation.
Trade-offs: Lowest latency and highest reliability at the cost of zero software telemetry directly from the supervisor.
Key IC selection
High-Voltage Buck Regulator for supervisor bias power
- Need: Step down industrial high-voltage DC bus (e.g., 24V/48V) to a stable low-voltage rail (e.g., 3.3V/5V) with high efficiency and robust transient tolerance.
- Class: Synchronous step-down DC-DC regulator (Wide Vin Buck)
- Shortlist: TI LM5164 family, ADI LTC7138 family
- Pick: Select based on maximum input voltage rating, quiescent current, and integrated switch specs to match input transient requirements.
High-Accuracy Window Supervisor
- Need: Monitor scaled DC bus voltage against tight over-voltage and under-voltage thresholds with high precision and fast response time.
- Class: High-accuracy voltage window supervisor / reset IC with open-drain output
- Shortlist: TI TPS3703 family, ADI MAX16132 family
- Pick: Select based on threshold accuracy percentage, adjustable hysteresis, and package thermal/footprint constraints.
High-Precision Voltage Scaling and Transient Protection
- Need: Accurately scale down high-voltage DC bus to match supervisor SENSE input range while maintaining low drift across industrial temperature extremes.
- Class: High-precision thin-film resistor divider network with ESD/TVS clamping
- Shortlist: Vishay MPM series thin-film dividers, Susumu RGA series
- Pick: Select based on voltage ratio, TCR matching (ppm/°C), and voltage rating to prevent breakdown.
Risk register
| ID | Area | Severity | Detail | Mitigation |
|---|---|---|---|---|
| r1 | emi | high | High-voltage DC bus switching noise and industrial transients coupled into the high-impedance VOLTAGE_SENSING_DIVIDER node can cause nuisance trips on the TPS3703_MONITOR. | Place filtering capacitors close to the SENSE pin, layout the divider with guard traces, and ensure robust TVS placement on the high-voltage input. |
| r2 | power | med | Resistor self-heating in the high-voltage divider chain can cause thermal drift, altering the effective UV/OV trip thresholds over wide industrial operating temperatures. | Use high-voltage thin-film resistors with tight TCR matching and distribute power dissipation across multiple series-parallel resistor packages if necessary. |
| r3 | supply | med | Direct hardware shutdown routing via open-drain outputs across noisy industrial cables/planes to enable pins may pick up ground bounce or EMI, causing erratic supply shutdowns. | Keep the HARDWARE_SHUTDOWN_LOGIC trace short, add a local pull-up resistor, and optionally include an RC filter or Schmitt-trigger buffer if routing spans across PCB sub-modules. |
Key Components
4/4 modules matched to real parts. See the BOM tab for the full component table.
Texas Instruments LM5164 High-Voltage Buck Regulator (LM5164DDAR)
LM5164DDAR is the exact match for the primary MPN LM5164 with standard reel packaging suffix, representing the correct D
Build Summary
- Difficulty: Advanced
- Estimated time: 4-6 hours
- Tools required: Inventory Management System, Antistatic Trays, Digital Microscope, Calipers, Solder Paste Stencil, SAC305 Solder Paste
See the Build tab for the full step-by-step assembly guide.
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