Ups boards
About the Ups boards PCB
Ups boards is an open source PCB design by LeoChizh, published on GitHub under the MIT license. It is a 2-layer board measuring 80 × 125 mm, with 22 components from 17 distinct parts.
Other key parts include the LM358 and NE555P. By type, the board carries 8 resistors, 6 capacitors, 2 ICs, 2 crystals, 2 diodes and 1 transistor.
It belongs with the power & battery designs in this gallery.
From the project
A current-limited, inrush-safe low-side load switch for a battery-backed UPS, built entirely from an NE555 timer and a dual op-amp — no dedicated hot-swap/current-limiter IC.
A current-limited, inrush-safe low-side load switch for a battery-backed UPS, built entirely from an NE555 timer and a dual op-amp — no dedicated hot-swap/current-limiter IC.
- Switches the return path to a load (in this build: a Raspberry Pi + WiFi router) through an N-channel MOSFET (Q1, IRFZ44N). - A current-sense amplifier (U1A) feeding a PWM comparator (U1B, both halves of one LM358) fold back the MOSFET's duty cycle as current rises, instead of a hard on/off cutoff or a linear-mode limiter (which would dissipate far more heat at these currents). - The PWM ramp comes from an NE555…
Main components on the Ups boards
Ups boards bill of materials (BOM)
22 components, 17 distinct parts.
| Qty | Part | Footprint | Refs |
|---|---|---|---|
| 1 | LM358 | DIP-8_W7.62mm | U1 |
| 1 | NE555P | DIP-8_W7.62mm | U2 |
| 1 | IRFZ44N | TO-220-3_Vertical | Q1 |
| 1 | Input | PhoenixContact_MSTBA_2,5_3-G-5,08_1x03_P5.08mm_Horizontal | X1 |
| 1 | Output | PhoenixContact_MSTBA_2,5_3-G-5,08_1x03_P5.08mm_Horizontal | X2 |
| 1 | 0R01 | R_Shunt_d1.2mm_L10mm | RSense1 |
| 1 | 8V2 | D_DO-35_SOD27_P7.62mm_Horizontal | D1 |
| 1 | LED | LED_D3.0mm_Clear | D2 |
| 3 | 47000uF | CP_Radial_D35.0mm_P10.00mm_SnapIn | C1, C2, C3 |
| 1 | 10nf | C_Rect_L7.2mm_W3.5mm_P5.00mm_FKS2_FKP2_MKS2_MKP2 | C4 |
| 1 | 10nf | C_Rect_L7.0mm_W3.5mm_P5.00mm | C5 |
| 1 | 100nf | C_Rect_L9.0mm_W3.3mm_P7.50mm_MKT | C6 |
| 1 | 680R | R_Axial_DIN0207_L6.3mm_D2.5mm_P10.16mm_Horizontal | R1 |
| 2 | 1k | R_Axial_DIN0207_L6.3mm_D2.5mm_P10.16mm_Horizontal | R2, R7 |
| 2 | 10k | R_Axial_DIN0207_L6.3mm_D2.5mm_P10.16mm_Horizontal | R3, R5 |
| 1 | 470k | R_Axial_DIN0207_L6.3mm_D2.5mm_P10.16mm_Horizontal | R4 |
| 2 | 10R | R_Axial_DIN0207_L6.3mm_D2.5mm_P10.16mm_Horizontal | R6, R8 |
Ups boards design files
The KiCad project lives in the LeoChizh/ups_boards repository on GitHub; these links point at the commit this page was built from.
- Layoutpcb2/pcb1.kicad_pcb
- Schematicpcb2/pcb1.kicad_sch
Ups boards: common questions
How big is the Ups boards PCB?
The Ups boards measures 80 × 125 mm, has 2 copper layers and is 1.6 mm thick.
How many components are on the Ups boards?
22 components, from 17 distinct parts. The full bill of materials is listed on this page.
Where can I download the Ups boards design files?
From the LeoChizh/ups_boards repository on GitHub, which has the KiCad layout and the schematic; the links under Design files point to each one.
Can I use the Ups boards design in my own project?
Yes, under the terms of its MIT license, which LeoChizh chose for the repository.
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