company blog about Supply TI Sequencers:Analog Power-Supply Sequencer,Digital Power-Supply Sequencer

Supply TI Sequencers:Analog Power-Supply Sequencer,Digital Power-Supply Sequencer

Shenzhen Mingjiada Electronics Co., Ltd., as a specialist supplier with extensive experience in the distribution of electronic components, provides customers with high-quality products and services through its stable supply chain resources, rigorous quality control system and efficient service capabilities.

Supply Advantages

We maintain close cooperation with original equipment manufacturers and major distribution channels to ensure that products are genuine and that stock levels are sufficient. We also offer both bulk procurement and small-batch sample services to meet our customers’ diverse procurement needs. All products supplied undergo rigorous quality testing; from source selection and incoming inspection to dispatch verification, every stage adheres to standardised procedures to eliminate counterfeit or substandard products, ensuring that every item received by the customer complies with the original manufacturer’s specifications and quality requirements.

TI Power Sequencers: Analogue Power Sequencers and Digital Power Sequencers

In multi-rail power supply systems, devices such as FPGAs, processors, ASICs, humanoid robot controllers and AI computing servers have strict requirements regarding the sequence of power-up and power-down. Incorrect sequencing can lead to device lock-up, surge damage and permanent chip damage. TI’s two main product lines—analogue and digital power sequencers—are designed for simple, low-cost sequencing scenarios and complex, multi-rail intelligent power management scenarios respectively, covering sectors such as industrial, communications, automotive, servers and automation equipment.

I. TI Analogue Power Sequencers

Principle of Operation

TI’s analogue power sequencers employ a pure hardware analogue architecture with no embedded firmware, relying on internal reference sources, comparators, RC delay circuits and open-drain driver units to perform timing control. The core logic is threshold-triggered: once the master enable signal becomes active, the first power rail is activated; when the voltage on that rail rises to the preset ‘POWER GOOD’ threshold, the hardware delay unit is triggered; upon expiry of the delay period, an enable signal is output to activate the next rail. Power-up occurs in a step-by-step manner, whilst power-down follows a reverse sequence; the entire process is executed automatically by the hardware without the need for software programming. Representative models include the LM3880 and LM3881 (LM388x series), as well as the TPS7H3014-SEP aerospace-grade analogue sequencer, which is suitable for high-reliability applications in Low Earth Orbit (LEO) satellites.

Key Features

1. Easy to use, no coding required: Available in versions with factory-set fixed delays and programmable versions requiring only a few external resistors. Power-up sequencing parameters are fixed, eliminating the need for host computer configuration; the device is ready for use simply by connecting the hardware.

2. Streamlined BOM and minimal PCB footprint: The LM3880 utilises a compact SOT-23 package, whilst the LM3881 uses a VSSOP-8 package; with very few external components, these are well-suited to space-constrained designs.

3. High reliability and low quiescent power consumption: With no digital logic units, there is no risk of firmware runaway, and they offer strong resistance to electromagnetic interference; The devices operate at 2.7V to 5.5V, making them suitable for mainstream low-voltage control domains.

4. Supports daisy-chain expansion: Multiple devices can be cascaded to increase the number of power rails, enabling the orderly start-up and shutdown of additional power supplies.

5. Suppresses inrush current and mitigates latch-up effects: By staggering the start-up times of each power supply, it prevents large inrush currents caused by simultaneous power-up of multiple rails, thereby protecting downstream chips.

Applications

Suitable for systems with 3 to 4 power rails, fixed sequencing logic, and no requirement for fault logging or remote monitoring: simple industrial control boards, small IoT modules, basic motor driver boards, and low-cost embedded motherboards. The LM3880-Q1 automotive-grade version is designed for power sequencing control in non-safety-critical automotive domains.

II. TI Digital Power Sequencers

Principle of Operation

TI’s digital power sequencers, centred on the UCD90x series (UCD9081, UCD9090, UCD90120A, UCD90160, UCD91160), are digital power management ICs featuring power health monitoring. They integrate a 12-bit ADC, non-volatile memory, a PMBus/I²C communication core and a PWM generator. Timing logic configuration is carried out on a PC using the TI Fusion Digital Power™ GUI software, with parameters programmed into the on-chip memory. Timing triggers support three modes: time-based, voltage threshold-based and pin-state-based; power-up and power-down sequences, as well as fault protection strategies, can all be customised graphically; Built-in multi-channel voltage monitoring provides real-time acquisition of voltages across all power rails; in the event of overvoltage or undervoltage faults, the device executes shutdown, alarm and fault logging. It supports remote reading of power supply status and fault history via PMBus, whilst certain models feature power margin adjustment for power supply reliability testing.

Key Features

1. Highly programmable with flexible timing: Each power rail’s power-up delay, power-down sequence and fault response strategy can be configured independently. The device supports complex branching timing sequences; product iterations require no major hardware modifications—only an update to the configuration file is needed.

2. Centralised monitoring of multiple power rails: A single chip supports timing and voltage monitoring for up to 16 power rails, and devices can be cascaded to further expand the number of channels; High-speed ADC sampling, with multi-level OV/UV alarm thresholds configurable independently for each power supply rail.

3. Comprehensive system fault management: Built-in non-volatile fault log automatically records fault types and voltage snapshots at the time of failure, facilitating system debugging and failure analysis; integrated watchdog and support for the ACPI power management specification.

4. PMBus digital communication: The host can remotely read power rail voltages, status and fault information; supports remote enable control, meeting the intelligent operation and maintenance requirements of servers and communication equipment; certain models integrate PWM output, supporting fan speed control and power margin testing.

5. Highly integrated, all-in-one power manager: Integrates a timing generator, voltage monitor, fault logger and digital interface onto a single chip, simplifying the management of complex multi-rail power trees.

Suitable Applications

Complex multi-rail power systems: high-density AI computing servers, network switches, high-end FPGA/SoC development boards, telecommunications base station equipment, automation equipment, and power management units for humanoid robots. The UCD series supports long-term online monitoring and fault diagnosis, making it the preferred solution for managing high-end power systems.

III. Summary of Selection Criteria: TI Analogue Power Sequencers vs Digital Power Sequencers

- Analogue power sequencers (LM388x): Low-cost, plug-and-play, with fixed hardware timing; suitable for simple systems with few power rails, fixed timing, and no requirement for remote monitoring.

- Digital power sequencers (UCD90x/UCD91x): Programmable timing, multi-rail monitoring, fault logging and PMBus communication; suitable for high-end systems with multiple power rails that require online monitoring, fault diagnosis and platform-based reusability.