The "Fever Reduction" of AI Servers: How Does Liquid Cooling Reshape the Chip Industry Chain When Air Cooling Fails?
Hello everyone, I'm your financial journalist. Today, we're going to discuss a topic that may sound a bit technical, but it's closely related to everyone's future AI experience: the revolution in AI server cooling.
If you follow tech news, you might have heard about how powerful NVIDIA's new chips are. However, few people realize that to prevent these powerful chips from overheating, data centers are undergoing a complete transformation from using fans to employing liquid cooling systems. This change not only alters the appearance of data centers but also presents huge new opportunities for manufacturers of "analog chips" in the semiconductor industry.
Let me break down this news in simple terms and explain the logic and business opportunities behind it.
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Why Are Fans No Longer Enough? The "Heat Crisis" of AI Chips
First, let's understand the context: Why do we need to switch to liquid cooling now?
Imagine 25 years ago; a standard data center rack (the large cabinet that houses servers) had a power capacity of only 5 kilowatts, roughly equivalent to several air conditioners running at the same time. Back then, all you needed were a few large fans to dissipate the heat.
But now, with the explosion of AI models, the number of GPUs (the core of AI computing) has increased dramatically, and the power consumption of individual chips has also soared. Today, the power capacity of a rack can exceed 100 kilowatts, and it could even reach 1 megawatt (1MW) in the future. That's like concentrating the electricity load of a small factory in one cabinet.
At this point, simply increasing the fan speed is no longer effective. Fans are not only noisy and power-consuming but also have low thermal conductivity, making it impossible to dissipate the intense heat. If the chip temperature gets too high, not only will its performance decline (due to frequency reduction), but it could also be damaged.
This is where liquid cooling comes in. NVIDIA, as a leader in the industry, has eliminated all fans in its latest Vera Rubin architecture, adopting 100% liquid cooling. In simple terms, it's like putting a "water-cooled vest" on the chip, allowing the coolant to flow directly over its surface and carry away the heat. It's much more effective than just using fans in hot weather.
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Who Is in Charge of Monitoring the Liquid Cooling System? The Surge in Sensors
Liquid cooling systems are not as straightforward as air cooling. They are complex systems that involve a cycle where coolant absorbs heat from the chip (a cold plate), flows to the Distribution Unit (CDU), undergoes heat exchange and filtration, and then returns. Any issue, such as a leak in a pipe, a malfunctioning pump, or a clogged filter, can cause the server to crash.
Therefore, liquid cooling systems require a large number of sensors to monitor various parameters:
1. Temperature sensors (the most basic but critical):
- In the past, we only measured the temperature of the CPU/GPU chips themselves.
- Now, we also measure the temperature of the coolant at the inlet and outlet. By calculating the temperature difference, we can assess the efficiency of heat exchange. If the difference decreases, it indicates poor cooling efficiency, and we may need to increase the pump speed.
- There are three types of sensors used: RTDs (platinum resistors, stable but expensive), thermistors (cheap and flexible, suitable for installation on pipes), and integrated temperature chips (high-precision, providing direct digital readings). Liquid cooling has increased the number of temperature measurement points significantly.
2. Pressure and flow sensors (the "pulse" of the system):
- Pressure is like blood pressure; abnormal pressure in the pipes could indicate a valve not being fully open or a clogged filter. A single CDU unit may need to monitor pressure at multiple points before and after the pump, as well as on both sides of the filter.
- Flow rate is like the speed of blood flow in the body. The coolant flow rate in data centers is very high (tens to hundreds of liters per minute).
- Pressure difference method: A throttle valve is placed in the pipe to measure the pressure difference before and after, which is simple and inexpensive but can impede flow.
- Ultrasonic method: Uses ultrasonic waves to measure flow rate; it doesn't impede flow and is suitable for high-flow rates but is more complex.
- Electromagnetic method: Uses the voltage generated by conductive liquid in a magnetic field; suitable for large-diameter pipes but requires conductive coolant.
- All these methods require chips like AFEs (Analog Front End) and ADCs (Analog-to-Digital Converters) to process the signals.
3. Leak detection (an added layer of safety):
- Air-cooled servers don't worry about leaks, but liquid-cooled servers do. A leak of coolant can be catastrophic if it comes into contact with the circuit board.
- Liquid detection ropes or electrodes are installed inside the server to detect leaks immediately. These are unique to liquid cooling systems.
Who Is in Charge of the Action? Motor Drivers Become a New Battlefield
If sensors are the "eyes," then motors are the "hands and feet" of the cooling system.
Traditional servers rely on fans for cooling, and fan motors are relatively simple. However, in liquid cooling systems, there are pumps to circulate the coolant, valves to control the flow direction, and even compressors in some cooling cycles.
- Pump drive: Pumps need precise control of speed to match the server's load. High loads require fast flow, while low loads require slow flow for energy efficiency. This requires high-precision motor controllers, gate drivers, and MOSFETs (power switching transistors).
- Valve control: The distribution of coolant depends on valves, which need to be able to open and close accurately and provide position feedback (using Hall sensors, for example).
- Energy efficiency is key: STMicroelectronics (ST) points out that cooling systems can account for up to 40% of AI data center energy costs. Therefore, the efficiency and control strategy of motor drivers are crucial. Companies that can make pumps more energy-efficient and precise will have a competitive advantage.
This means that chip manufacturers not only need to sell sensors but also complete motor drive chips and control MCUs.
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How Are Major Players and Newcomers Competing in the Liquid Cooling Market?
Facing this new market, chip manufacturers are adjusting their strategies. Some are trying to be generalists, while others are focusing on specific areas:
1. TI (Texas Instruments) and NXP (NXP): These giants have a wide range of analog chips (ADCs, amplifiers, sensor interfaces, etc.) used in automotive, home appliances, and building automation. Their strategy is to reapply existing technologies from HVAC (heating, ventilation, and air conditioning) to data center liquid cooling. Their advantage lies in mature products, high reliability, and quick time to market. They provide reference designs to help customers build complete cooling monitoring systems.
2. ADI (Analog Devices): ADI specializes in high integration. They have launched the ADT7604, a multi-functional chip that can monitor temperatures and leak signals from 20 channels simultaneously. Their advantage is high integration, reducing the need for additional circuits and making it suitable for space-constrained servers.
3. ST (STMicroelectronics) and Infineon: These companies are strong in power semiconductors and motor drives. Their focus is on driving and controlling high-power motors, which are key components in liquid cooling systems.
4. Allegro: Allegro specializes in sensors and drivers. They don't offer MCUs or general-purpose ADCs but focus on sensor interfaces and drivers for specific applications.
5. Domestic manufacturers: Chinese companies like Sanbang Microelectronics and Naxin Microelectronics are quickly entering the market, looking for breakthroughs. For example, Sanbang Microelectronics has released the SGM451L for server temperature monitoring, with high precision for both local and remote temperature measurements (including internal diodes of CPUs/GPUs). Naxin Microelectronics has identified liquid cooling as a new direction and already offers products for pressure, temperature, and current detection.
6. Current Status: While domestic manufacturers have fewer specialized products in the liquid cooling market, the growing demand for AI servers presents a huge opportunity.
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Future Trends: From "Single-Point Alerts" to "Intelligent Integration"
Current liquid cooling systems often rely on simple alerts (e.g., pressure or temperature thresholds). The future direction is towards sensor integration and edge AI:
- Multi-signal correlation: Parameters like pump current, speed, pressure, flow rate, temperature, and humidity are interrelated. For example, a sudden increase in pump current could indicate a clogged filter, not a faulty pump.
- Intelligent decision-making: Future CDUs will have built-in AI processors to analyze all signals, assess system health, and even predict failures.
- Upgraded chip requirements: This means an increase in the demand for high-channel ADCs, high-performance AFEs, and MCUs with edge computing capabilities.
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In Summary
The adoption of liquid cooling in AI servers is not just an upgrade in cooling technology but also a structural opportunity for the analog chip industry:
- For investors: Pay attention to chip companies with expertise in temperature, pressure, and flow sensors, as well as motor drives and high-precision ADCs. Both international giants (TI, ADI, ST, NXP) and domestic companies (Sanbang Microelectronics, Naxin Microelectronics) are accelerating their efforts in this area.
- For the industry: Liquid cooling will become a standard in AI infrastructure, driving long-term growth in related industries such as sensors, pumps and valves, coolants, and control systems.
In short, the smarter the AI, the hotter the servers become, and the more important liquid cooling becomes—making analog chips even more valuable. This is the core logic behind this news.