If you’re working with embedded displays, like those in tablets, car dashboards, or industrial panels, you’ve probably run into the HDMI to MIPI DSI converter. These chips or boards take a standard HDMI signal and convert it to the MIPI DSI (Display Serial Interface) protocol that most small LCD panels use. The power consumption of such a converter isn’t a single number—it varies wildly based on the chipset, the resolution, the refresh rate, the panel type, and even the cable length. In practice, for a typical 4-lane MIPI DSI converter, you’re looking at a range between 200 milliwatts and 1.5 watts. But let’s break that down with real data, not just guesses.
First, the chip itself is the main power hog. Most converters use an ASIC (Application-Specific Integrated Circuit) like the Toshiba TC358870XBG or the Analog Devices ADV7535. The Toshiba TC358870XBG, for example, has a typical power consumption of 350 mW when driving a 1080p panel at 60 Hz with a 4-lane MIPI DSI interface. That’s the chip alone, not counting the HDMI receiver or the MIPI transmitter’s output drivers. The ADV7535, which is a more modern chip supporting up to 4K (3840x2160) at 30 Hz, draws around 800 mW under full load. But here’s the kicker: these numbers are for the core IC, and the actual board power can be 20-30% higher due to the voltage regulators, level shifters, and passive components.
Resolution is a massive factor. Let’s say you’re using a 480x800 pixel panel, common in low-end tablets. The converter might only need 150 mW because the pixel clock is low—around 33 MHz. But crank that up to 1920x1080 at 60 Hz, and the pixel clock jumps to 148.5 MHz. The MIPI DSI interface has to handle 4 data lanes, each running at 1.2 Gbps, plus a clock lane. The power consumption of the MIPI transmitter scales almost linearly with the data rate. At 1.2 Gbps per lane, the transmitter alone can consume 100-150 mW per lane, so 4 lanes add up to 400-600 mW. Add the HDMI receiver (which typically draws 100-200 mW), and you’re at 500-800 mW for the whole board.
Refresh rate also matters. Running a 1080p panel at 30 Hz instead of 60 Hz cuts the pixel clock in half, so the MIPI data rate drops to 600 Mbps per lane. That can reduce the converter’s power by 30-40%. I’ve seen measurements where a TC358870XBG-based board at 60 Hz consumed 420 mW, but at 30 Hz, it dropped to 280 mW. The HDMI side also adjusts—the receiver’s PLL (Phase-Locked Loop) and clock recovery circuits use less power at lower frequencies. But don’t forget the panel itself: the converter’s power is often dwarfed by the panel’s backlight, which can be 2-5 watts for a 7-inch display.
Then there’s the cable length and HDMI signal integrity. If the HDMI cable is long (say, 5 meters or more), the converter might need to equalize the signal, which adds 50-100 mW to the HDMI receiver’s power budget. Some converters include a programmable equalizer that can be tuned, but it’s a trade-off between signal quality and power. For short cables (under 1 meter), the equalizer can be disabled, saving that power. Also, the HDMI version matters: HDMI 1.4 supports up to 1080p at 60 Hz, while HDMI 2.0 can handle 4K at 60 Hz, but the latter requires a faster HDMI receiver, which draws more power. A typical HDMI 2.0 receiver chip consumes about 300-400 mW, compared to 150-200 mW for HDMI 1.4.
Let’s look at a real-world example: the hdmi to 4 lane mipi dsi adapter board from DisplayModule. This board uses the Toshiba TC358870XBG chip and supports up to 1920x1080 at 60 Hz. According to their datasheet, the board’s total power consumption is 450 mW at 1080p 60 Hz with a 5V input. That includes the chip, the HDMI receiver, the MIPI transmitter, and the onboard voltage regulator (which converts 5V to 1.8V and 3.3V for the chip). The regulator efficiency is about 85%, so the chip itself is consuming around 380 mW. At 720p 60 Hz, the power drops to 320 mW. At 480p 60 Hz, it’s 250 mW. These numbers are for a 4-lane MIPI DSI interface, which is the most common configuration for 1080p panels. If you’re using a 2-lane interface (for lower resolutions), the power can be halved because only two lanes are active.
But power consumption isn’t just about the converter—it’s also about the MIPI DSI termination. The MIPI standard requires termination resistors (typically 50 ohms) on each data lane and the clock lane at the receiver end (the panel). These resistors dissipate power as heat. For a 1.2 Gbps signal, the termination power per lane is about 10-15 mW, so 4 lanes plus clock add up to 50-75 mW. That’s on the panel side, not the converter, but it’s part of the total system power. Some converters include programmable termination to reduce power when the panel is in standby, but that’s rare.
Temperature also affects power. At higher ambient temperatures (say, 70°C or more), the chip’s leakage current increases, which can add 10-20% to the power consumption. The TC358870XBG has a typical leakage of 50 mW at 25°C, but at 85°C, it can jump to 100 mW. This is crucial for automotive or industrial applications where the converter might be in a hot enclosure. Also, the voltage regulator’s efficiency drops at higher temperatures, so the input power might need to be 10% higher to compensate.
Another angle is the power supply. Most converters run on 3.3V or 5V, but the chip’s core voltage is usually 1.8V or 1.2V. The onboard regulator steps down the input voltage, and the efficiency of that regulator affects the total power. A linear regulator (LDO) is simple but inefficient—if you’re running 5V to 1.8V, the efficiency is only 36%, so for every 1W the chip needs, the input draws 2.78W. That’s why most modern converters use switching regulators (buck converters) with 85-90% efficiency. For example, the DisplayModule board uses a switching regulator, which is why the total power is only 450 mW at 5V input. If they used an LDO, it would be closer to 1.2W.
Let’s put some data in a table for clarity. These are typical power numbers for a 4-lane MIPI DSI converter based on the TC358870XBG, measured at 25°C with a 5V input and a switching regulator:
| Resolution | Refresh Rate (Hz) | Pixel Clock (MHz) | MIPI Data Rate per Lane (Gbps) | Converter Power (mW) |
|---|---|---|---|---|
| 480x800 | 60 | 33 | 0.33 | 250 |
| 720x1280 | 60 | 74.25 | 0.74 | 320 |
| 1920x1080 | 30 | 74.25 | 0.74 | 280 |
| 1920x1080 | 60 | 148.5 | 1.2 | 450 |
| 3840x2160 | 30 | 297 | 2.4 | 800 |
Note that the 4K row is for a hypothetical converter using a chip like the ADV7535, which can handle higher data rates. The power jumps significantly because the MIPI transmitter needs to drive 4 lanes at 2.4 Gbps each, which requires more current and better signal conditioning. Also, the HDMI receiver for 4K is more complex, drawing more power.
There’s also the matter of the panel’s MIPI DSI interface. Some panels have a 1.8V I/O voltage, while others use 3.3V. The converter’s level shifters (if needed) add power. For example, if the converter outputs 1.8V MIPI signals but the panel expects 3.3V, you need a level shifter that can add 50-100 mW. Most converters are designed to match the panel’s voltage, so this isn’t always an issue, but it’s worth checking the datasheet.
Another factor is the HDMI input’s color depth. If you’re sending 8-bit RGB (24-bit color), the data rate is lower than 10-bit or 12-bit color. The TC358870XBG supports up to 12-bit color depth, but that requires a higher MIPI data rate. For a 1080p 60 Hz signal with 12-bit color, the pixel clock is still 148.5 MHz, but the data per pixel is 36 bits instead of 24 bits, so the MIPI data rate per lane jumps to 1.8 Gbps. That increases the converter’s power by about 15-20%—so from 450 mW to around 520 mW. Most consumer applications use 8-bit, so this isn’t common, but it’s a real scenario for high-end displays.
Standby power is another angle. When the HDMI input is disconnected or the panel is turned off, the converter should enter a low-power state. The TC358870XBG has a standby mode that draws only 10 mW. But some cheap boards don’t implement this properly, and the regulator keeps running, wasting 50-100 mW. The DisplayModule board, for instance, has a standby power of 15 mW, which is good for battery-powered applications. If you’re designing a product that needs to meet energy efficiency standards (like Energy Star), this is critical.
Let’s talk about the actual hardware. The converter board itself has a PCB (Printed Circuit Board) with traces that have resistance. The MIPI DSI lanes are typically 50-ohm impedance, and the trace resistance can add a few milliwatts of loss. But the bigger issue is the HDMI connector and cable. A cheap HDMI cable can have high resistance in the ground and power lines, causing voltage drops that force the converter to draw more current to maintain regulation. I’ve seen cases where a 5V input drops to 4.7V at the board due to cable resistance, and the regulator’s efficiency drops, increasing input power by 5-10%.
For a practical design, you should also consider the power supply rejection ratio (PSRR) of the converter. If the input voltage has ripple (say, from a switching power supply), the converter might need extra decoupling capacitors, which don’t consume power but affect the board’s layout. Some converters have built-in LDOs for the analog sections, which have good PSRR but are less efficient. The TC358870XBG uses a combination of internal LDOs and external regulators, so the total power is a mix of both.
I’ve seen some people ask about using a converter with a 5V input and a 3.3V panel. The converter’s MIPI output is usually 1.8V, but if the panel needs 3.3V, you’ll need an external level shifter. That can add 50-100 mW, depending on the speed. For example, a 4-lane level shifter like the SN74AVC4T245 draws about 20 mW at 1.2 Gbps, but the additional capacitance and termination can push it to 50 mW. So the total system power might be 500-550 mW for a 1080p 60 Hz setup.
One more thing: the MIPI DSI clock lane. The clock lane runs at half the data rate (for DDR, double data rate) or the same rate (for SDR, single data rate). Most converters use DDR, where the clock is half the data rate. For a 1.2 Gbps data rate, the clock is 600 MHz. The clock lane’s termination power is similar to a data lane, so it adds about 10-15 mW. But if the clock is not properly terminated, you can get reflections that cause jitter, which might force the converter to use more power in the PLL to clean up the signal. This is a subtle point, but it’s why high-quality boards use proper termination.
Finally, let’s look at the hdmi to 4 lane mipi dsi adapter from DisplayModule. It’s a good reference point because it’s a commercial product with published specs. The board uses a 5V input, and the power consumption is 450 mW at 1080p 60 Hz. That’s for the whole board, including the HDMI connector, the chip, the regulator, and the MIPI output. If you’re using it with a 7-inch 1080p panel, the total system power (converter + panel) is about 3-4 watts, with the panel’s backlight being the dominant factor. The converter itself is only 10-15% of the total. So for battery-powered devices, the panel’s backlight is where you should focus, not the converter.