In 2025, during the Spring Festival, DeepSeek released its new AI model R1, breaking through the technical boundaries of large models in China with parameters on the scale of billions, marking the entry of compute-driven artificial intelligence into the deep waters of industrialization. In the core infrastructure of compute power, centered around GPUs, CPUs, and Switch chips, the multi-phase low-voltage high-current power supply (multi-phase controller + Smart Power Stage) serves as the driving force of the "compute engine," facing stringent challenges brought by large model iterations. The peak power consumption of —— compute chips has surpassed the kilowatt level, with transient load fluctuations reaching the thousand-ampere level.

In order to meet customers' demand for multi-phase power supply in terms of high power density, high efficiency and high reliability, IVS has launched 12-phase dual-output controller IS6203A, which provides an efficient and stable power supply solution for AI computing chips.

The figure shows the application of multi-phase power supply scheme in AI server

Core features

Multi-phase architecture and dynamic management:

IS6203A supports dual-output configuration, with Loop1 supporting up to 12 phases and Loop2 supporting up to 6 phase buck conversion, providing stable power supply for high-current loads. Its Dynamic Phase Synchronization (APS) can automatically adjust the number of operating phases based on the load: reducing the number of phases at light loads to improve efficiency, and increasing the number of phases at heavy loads to distribute heat and reduce temperature, optimizing energy efficiency and improving thermal performance.

High precision voltage regulation

GPU, CPU and other chips have very high requirements for voltage stability, and small voltage fluctuations may lead to system instability or performance decline. IS6203A ensures stable and reliable output voltage through precision algorithm and feedback mechanism, and the output voltage regulation accuracy reaches ±0.5%.

Programmable and PMBus interface

IS6203A supports configuration and monitoring of power status via the PMBus interface. Users can flexibly set parameters such as output voltage, current limits, number of operating phases, and switching frequency through software, simplifying the design process. Additionally, users can read real-time data on operating status and temperature, facilitating debugging and fault diagnosis.

Comprehensive protection function

To ensure the system's safety and reliability, IS6203A integrates various protection functions, including overvoltage protection, undervoltage protection, overcurrent protection, and overheating protection. In case of overvoltage, it automatically prevents the output voltage from exceeding the safe range and damaging the load chip; undervoltage protection ensures that the output voltage is no less than the set value; overcurrent protection limits the output current overload; overheating protection automatically shuts off the output when the chip temperature is too high, preventing thermal damage.

Supports a variety of communication protocols and common packages

IS6203A Integrates PMBus, AVSBus, SVID, PVID and other communication protocols to meet the requirements of most mainstream chips such as GPU and CPU. The chip uses QFN-48 package, 6mm x 6mm size, compatible with the products of mainstream manufacturers such as Infineon and MPS to ensure a wider range of applicability.

The figure shows the IS6203A pin package and typical application block diagram

Important design indicators

High reliability

After the VCC power is turned on, the IS6203A can automatically detect whether the PWM signal is floating. If it detects that the PWM is floating, the system will consider that phase Power stage is not properly soldered and ignore this phase, while the other phases continue to operate normally. In actual operation, the IS6203A supports Fault-handling behavior functionality. When a fault occurs in a certain phase Power stage, the controller can detect and discard that phase, allowing the other phases to continue operating normally.

Below is the waveform when a phase Power stage triggers OTP in actual work: When the first phase triggers OTP, T_sen is first pulled up to 3.3V, and at the same time, phase Power stage no longer responds to the controller's PWM signal. Then, I_mon voltage is reduced to REF=0.8V, which means I_mon = 0A. After receiving the Tsen and I_mon signals, the controller immediately switches the PWM signal to tri-state. The following figure shows the waveform when IS6203A triggers OTP protection:

High efficiency

IS6203A Supports automatic phase lifting (APS) function, which keeps working at the optimal number of phases according to the size of the load current, thus significantly improving the efficiency under light load, and fully improving the thermal performance design when all phases work at full load. The waveform diagram of the number of phases changing when the load current increases is as follows:

In the case of V_in=12V, V_out=0.7V, 8 phases are used and F_sw is 600kHz. The efficiency comparison curve of turning on and off the automatic phase lifting and lowering (APS) function is as follows:

In the case of V_in=12V, V_out=0.7V, 10 phases are used to work, and F_sw is 600kHz. The efficiency comparison curve between opening and closing the automatic phase lifting and lowering (APS) function is as follows:

Fast dynamic response

The instantaneous dynamic regulation of IS6203A can adapt to the application scenarios where the back-end load changes rapidly. When the back-end load changes rapidly, the range of voltage change is small, and the V_peak-peak value is 214.4mV, which fully meets the customer's requirements. The specific test conditions are as follows:

V_in=12V, V_out1=1.8V, LL=0.5mohm

I_start=60A, I_end=430A, Slew rate=960A/us

Load frequency=2kHz, Duty cycle=50%

C_out=7868uF （MLCC：49*100uF+16*47uF+79*22uF+8*1uF，POSCAP：1*470uF）

The figure shows the dynamic test waveform

High precision current Imon report

The following figure shows the Imon reporting curve tested by IS6203A. The accuracy of Imon can reach ±3%, providing accurate current monitoring capability.

Compatibility test

IS6203A It can be used in combination with our 70A/90A/100A Power stage, and at the same time supports the application of mainstream Power stage solutions on the market. The verified solutions on multiple main platforms are as follows: