Game Gear Power board

This work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.

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I have developed a replacement power board specifically designed for the new SYF Mainboard. While its primary compatibility lies with the SYF Mainboard, it can also function with the original SEGA Game Gear under certain conditions.

It's important to note that this board is compatible with the original Game Gear, it does not include a 34V voltage regulator. Therefore, it will only function with an original SEGA Game Gear if the LCD screen has been replaced with a modern LCD TFT (IPS) kit.

The power board offers two power source options: a 3.7V LiPo battery or a USB-C connection. To prioritize power from the USB source, I have implemented a MOSFET load sharing circuit. When the USB is connected, it takes precedence, while simultaneously charging the LiPo battery using a Microchip MCP73833/4 battery management controller.

Given that the Game Gear requires a 5V power supply, I have chosen a TI TPS61032 step-up power regulator. This regulator efficiently converts the lower voltage to the required 5V. Additionally, it features a low-battery comparator thattriggers a VREF change, enabling the low-battery indicator on the Game Gear.

DIP Switches

The DIP switches offer flexibility and customization, allowing you to tailor the power board's functionality based on your specific console version, battery charging capabilities, and LCD screen requirements.

The power board I have developed features three DIP switches that provide various options and functionalities:

    1. VA0 / VA1: This switch enables a more stable low battery indicator specifically designed for the original Sega dual-ASIC VA0 console. For the VA1 and all SYF mainboards, it is recommended to keep the switch set to VA1.
    2. 1.0A / 0.5A: This switch allows you to choose the maximum battery charging current. The appropriate setting depends on the capabilities of your USB-C power brick and the batteries you are using. If your power brick can deliver 1.5A and your batteries can handle 1.0A charging current, you can switch it to 1.0A. However, if you are unsure or using different specifications, it is recommended to keep the switch set to 0.5A.
    3. 34V / 5V: This switch is only available on the 34V version of the board. With this option, you can enable or disable the output of 34V to pin 9 of the connector. This feature is particularly relevant when using the board with the original SEGA Game Gear LCD, the requires 34V for the contrast circuit. Please note that this switch is not applicable to boards without a 34V voltage regulator

      LiPo battery recommendation

      I have been testing with the following sizes LiPo batteries:

        ​The 124050 is the maximum size that fits into the battery component. I strongly recommend a larger 2500-3000mAh battery in case you use a less power efficient LCD screen (McWill, RetroKai, Funnyplaying).

        Gerber

        In case you like to make your own board, you can download the gerber, BOM and PNP files here. Keep in mind the project has a Attribution-NonCommercial-ShareAlike 4.0 International (CC BY-NC-SA 4.0) license.

        ​USB-C cover

        To cover the hole of the DC jack, you can 3D print this STL. I recommend you to print it with a transparent type of plastic, so the charging status LEDs will be visible.

        BOM

        Comment Designator Footprint LCSC Part
        1uF C1 0603 C106248
        100nF C2 0603 C14663
        10uF C3 0603 C326057
        1uF C4 0603 C106248
        10pF C5 0603 C106245
        220uF C6 CASE_B2 C79111
        1uF C7 0603 C106248
        1uF C8 0603 C106248
        100nF C9 0603 C14663
        292161-9 CN1 Plugin,P=2mm C225342
        TYPE-C-31-M-29 CN2 SMD C2689969
        PD3S230 D1 DI323 C460243
        TPS61030 IC1 TSSOP-16 C9842
        MCP73833T-AMI/UN IC2 MSOP-10 C627668
        SN74LVC1G14 IC3 SOT23-5 C7835
        6.8uH L1 6060 C285805
        YELLOW-GREEN LD1 0606 C264500
        AO3401A Q1 SOT-23-3 C15127
        47K R1 0603 C105579 
        51R R2 0603 C114628 
        4.7K R3 0603 C99782
        4.7K R4 0603 C99782
        2.49M R7 0603 C482797
        470K R8 0603 C114622
        1.8M R9 0603 C137772
        200K R10 0603 C105574
        220R R11 0603 C107696
        1.1K R12 0603 C137780 
        1.1K R13 0603 C137780 
        1K R14 0603 C22548 
        470K R15 0603 C114622
        3K R16 0603 C126358 
        1.8K R17 0603 C185354 
        10K R18 0603 C98220 
        SSSF121900 SW1 SMD C97449
        DSHP03TS-S SW2 SMD-6P C319051