Child Safe RGB Badge

flux

I’ll remove the per-LED WS2812B decoupling capacitors that were added despite the V6 datasheet feature note, then re-run checks and update the safety/power notes accordingly.

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Removed C24–C43, the per-LED WS2812B-2020-V6 capacitors, and kept the shared LED-rail bulk capacitor C5. Re-ran checks: no open ERC/passive warnings found.
Updated:
V

vasy_skral

J1 need PCB cutout, replace it with TYPE-C 16PIN 2MD(073)

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I’ll replace J1 with the requested TYPE-C 16PIN 2MD(073), first finding the exact library part and preserving the existing USB-C nets, then I’ll verify the connector pins/checks afterward.

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Replaced J1 with TYPE-C 16PIN 2MD(073) (LCSC C2765186) and restored the existing power-only USB-C wiring:
  • VBUS pins → VBUS_RAW
  • GND + shell pins → GND
  • CC1/CC2 → existing CC pulldown/ESD nets
  • DP/DN/SBU pins marked no-connect
Verified J1 schematic connectivity and ran targeted ERC/DRC checks; no J1-related open issues were reported.
Verify connector and layout
Place J1 at edge
Run full DRC
Verify cutout geometry
Update bring-up docs
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Files

Schematic

Layout

Preview

D2
U1
J1
U3
LED20
LED3
LED7
LED6
LED14
LED15
LED4
LED2
LED8
LED17
LED10
LED16
LED18
LED19
LED11
LED13
LED1
LED12
LED5
LED9
U1 DVDD - C11 P1
F2 P2 - C5 P1
U1 RUN - TP3 P1
LED2 DO - LED3 DI
L1 2 - U1 VREG_FB
LED14 DO - LED15 DI
U1 XIN - Y1 CRYSTAL_1
F2 P2 - C5 P1
C3 P1 - SW1 ~
F2 P2 - C5 P1
LED9 DO - LED10 DI
U1 SWCLK - TP2 P1
U1 GPIO4 - SW2 P1
U1 IOVDD - U1 USB_OTP_VDD
U1 IOVDD - U1 USB_OTP_VDD
LED4 DO - LED5 DI
LED13 DO - LED14 DI
R7 P2 - R8 P1
U2 STAT - R4 P1
U1 GPIO4 - SW2 P1
LED11 DO - LED12 DI
LED17 DO - LED18 DI
U1 XOUT - Y1 CRYSTAL_2
U1 IOVDD - U1 USB_OTP_VDD
C3 P1 - SW1 ~
U3 EN - SW1 ~
U1 DVDD - C11 P1
U1 VREG_LX - L1 1
F2 P2 - C5 P1
U1 IOVDD - U1 USB_OTP_VDD
J1 CC1 - R1 P1
L1 2 - U1 VREG_FB
U1 XIN - Y1 CRYSTAL_1
F1 P2 - D1 1
U1 GPIO4 - SW2 P1
C3 P1 - SW1 ~
LED1 DO - LED2 DI
U1 DVDD - C11 P1
F2 P2 - C5 P1
U1 XOUT - Y1 CRYSTAL_2
LED2 DO - LED3 DI
U3 EN - SW1 ~
F2 P2 - C5 P1
J1 CC2 - R2 P1
R11 P2 - R12 P1
J1 CC1 - R1 P1
LED12 DO - LED13 DI
U2 PROG - R3 P1
LED8 DO - LED9 DI
LED9 DO - LED10 DI
F1 P2 - D1 1
F2 P2 - C5 P1
R6 P2 - LED1 DI
U1 IOVDD - U1 USB_OTP_VDD
U1 IOVDD - U1 USB_OTP_VDD
R11 P2 - R12 P1
F1 P2 - D1 1
F2 P2 - C5 P1
LED19 DO - LED20 DI
U1 DVDD - C11 P1
F2 P2 - C5 P1
F2 P2 - C5 P1
R7 P2 - R8 P1
R9 P2 - U1 VREG_AVDD
LED1 VDD - LED2 VDD
U1 IOVDD - U1 USB_OTP_VDD
F2 P2 - C5 P1
LED15 DO - LED16 DI
LED13 DO - LED14 DI
F2 P2 - C5 P1
LED8 DO - LED9 DI
U3 EN - SW1 ~
R11 P2 - R12 P1
F2 P2 - C5 P1
U1 SWCLK - TP2 P1
U1 IOVDD - U1 USB_OTP_VDD
LED12 DO - LED13 DI
LED16 DO - LED17 DI
LED3 DO - LED4 DI
LED18 DO - LED19 DI
J2 P1 - F3 P1
F2 P2 - C5 P1
J1 VBUS - F1 P1
U1 IOVDD - U1 USB_OTP_VDD
LED18 DO - LED19 DI
U1 GPIO6 - R6 P1
U1 IOVDD - U1 USB_OTP_VDD
U1 GPIO6 - R6 P1
R11 P2 - R12 P1
LED15 DO - LED16 DI
U1 RUN - TP3 P1
LED5 DO - LED6 DI
J1 CC1 - R1 P1
LED16 DO - LED17 DI
F2 P2 - C5 P1
U1 SWDIO - TP1 P1
F2 P2 - C5 P1
U1 XOUT - Y1 CRYSTAL_2
F2 P2 - C5 P1
C3 P1 - SW1 ~
F2 P2 - C5 P1
LED11 DO - LED12 DI
U1 IOVDD - U1 USB_OTP_VDD
F2 P2 - C5 P1
LED1 VDD - LED2 VDD
R9 P2 - U1 VREG_AVDD
F1 P2 - D1 1
LED19 DO - LED20 DI
J1 CC1 - R1 P1
U1 GPIO4 - SW2 P1
R9 P2 - U1 VREG_AVDD
J2 P1 - F3 P1
J1 VBUS - F1 P1
U1 IOVDD - U1 USB_OTP_VDD
LED3 DO - LED4 DI
F2 P2 - C5 P1
L1 2 - U1 VREG_FB
J1 CC2 - R2 P1
LED1 VDD - LED2 VDD
LED1 VDD - LED2 VDD
U1 XIN - Y1 CRYSTAL_1
J1 CC2 - R2 P1
U2 STAT - R4 P1
LED4 DO - LED5 DI
U3 EN - SW1 ~
LED14 DO - LED15 DI
U1 SWDIO - TP1 P1
U1 IOVDD - U1 USB_OTP_VDD
F2 P2 - C5 P1
LED6 DO - LED7 DI
U1 IOVDD - U1 USB_OTP_VDD
U1 IOVDD - U1 USB_OTP_VDD
LED7 DO - LED8 DI
U2 PROG - R3 P1
R6 P2 - LED1 DI
F2 P2 - C5 P1
C3 P1 - SW1 ~
J1 CC2 - R2 P1
R7 P2 - R8 P1
LED7 DO - LED8 DI
C3 P1 - SW1 ~
LED10 DO - LED11 DI
LED10 DO - LED11 DI
LED5 DO - LED6 DI
F1 P2 - D1 1
LED1 DO - LED2 DI
U1 DVDD - C11 P1
LED6 DO - LED7 DI
LED1 VDD - LED2 VDD
LED1 VDD - LED2 VDD
LED1 VDD - LED2 VDD
U2 STAT - R4 P1
LED17 DO - LED18 DI
U1 IOVDD - U1 USB_OTP_VDD
F1 P2 - D1 1
U1 VREG_LX - L1 1
C19
Capacitance
100nF
C11 P2 - C12 P2
C9
Capacitance
4.7uF
J1 EH - D1 2
C22
Capacitance
100nF
LED1 GND - LED2 GND
J1 EH - D1 2
C11 P2 - C12 P2
C8
Capacitance
15pF
C4 P2 - C5 P2
C44
Capacitance
100nF
C4 P2 - C5 P2
LED1 GND - LED2 GND
J1 EH - D1 2
C11 P2 - C12 P2
J1 EH - D1 2
C4 P2 - C5 P2
LED1 GND - LED2 GND
SW2 P2 - C6 P2
C23
Capacitance
100nF
J1 EH - D1 2
C11
Capacitance
4.7uF
LED1 GND - LED2 GND
R10 P2 - R12 P2
C4 P2 - C5 P2
C10
Capacitance
100nF
C4 P2 - C5 P2
C15
Capacitance
100nF
C4 P2 - C5 P2
J1 EH - D1 2
C16
Capacitance
100nF
C4 P2 - C5 P2
C4 P2 - C5 P2
C2
Capacitance
4.7uF
J1 EH - D1 2
LED1 GND - LED2 GND
R10 P2 - R12 P2
C4 P2 - C5 P2
C4 P2 - C5 P2
LED1 GND - LED2 GND
J1 EH - D1 2
SW2 P2 - C6 P2
J1 EH - D1 2
LED1 GND - LED2 GND
C5
Capacitance
22uF
LED1 GND - LED2 GND
C4 P2 - C5 P2
C17
Capacitance
100nF
J1 EH - D1 2
C4 P2 - C5 P2
C4 P2 - C5 P2
LED1 GND - LED2 GND
C3
Capacitance
4.7uF
LED1 GND - LED2 GND
LED1 GND - LED2 GND
SW2 P2 - C6 P2
LED1 GND - LED2 GND
C4
Capacitance
1uF
LED1 GND - LED2 GND
C13
Capacitance
100nF
LED1 GND - LED2 GND
C4 P2 - C5 P2
C11 P2 - C12 P2
C6
Capacitance
100nF
LED1 GND - LED2 GND
C11 P2 - C12 P2
C14
Capacitance
100nF
J1 EH - D1 2
R10 P2 - R12 P2
LED1 GND - LED2 GND
C11 P2 - C12 P2
C11 P2 - C12 P2
C18
Capacitance
100nF
C4 P2 - C5 P2
C21
Capacitance
100nF
C20
Capacitance
100nF
R10 P2 - R12 P2
LED1 GND - LED2 GND
J1 EH - D1 2
C1
Capacitance
4.7uF
LED1 GND - LED2 GND
LED1 GND - LED2 GND
C7
Capacitance
15pF
C12
Capacitance
4.7uF
LED1 GND - LED2 GND
C4 P2 - C5 P2
C11 P2 - C12 P2
R1
Resistance
5.1kΩ
F3
TP1
SW2
L1
Inductance
3.3uH
F2
R2
Resistance
5.1kΩ
R12
Resistance
1MΩ
TP5
R10
Resistance
100kΩ
TP2
D1
SW1
R3
Resistance
10kΩ
R6
Resistance
330Ω
Y1
R9
Resistance
33Ω
R7
Resistance
1MΩ
R8
Resistance
1MΩ
TP3
R5
Resistance
10kΩ
R4
Resistance
10kΩ
TP4
R11
Resistance
1MΩ
F1
U2
J2
Power Budget and Safety Notes
Status
Draft schematic is ERC-clean, but not production-ready for a child-worn product until the open safety items below are resolved and validated.
Selected Power Architecture
  • USB-C 5 V input -> F1 500 mA PTC -> VBUS_CHG -> MCP73832 charger -> F3 battery-side PTC -> protected 1S LiPo connector.
  • Battery/system rail -> SW1 electronic enable -> AP2112K-3.3 LDO -> 3V3 MCU rail.
  • 3V3 -> F2 200 mA hold PPTC -> 3V3_LED branch for the 20 WS2812B-2020-V6 LEDs.
  • Charger STAT is pulled up to 3V3 and read by RP2354A GPIO5.
  • VBUS_CHG is divided by R11/R12 and read by GPIO27_ADC1 so firmware can distinguish USB absent from charge complete.
Load Budget

Table

LoadRailDesign LimitWorst Case if UnrestrictedNotes
RP2354A + support3V330-80 mA targetTBDDepends clock and firmware.
LED branch3V3_LEDF2 200 mA hold plus firmware limit~720 mA to 1.2 A depending LED lot/datasheet assumptionDo not allow full-white sustained patterns.
Charger/status/dividers3V3/VBAT/VBUS<10 uA to a few mALowR7/R8 now fed from PWR_EN, not always-on VBAT.
Regulator Check
AP2112K-3.3 is rated 600 mA minimum. The LED branch is now isolated by F2 so the MCU rail is less exposed to LED faults, but F2 is not a precision current limiter. Thermal testing is still required.
Charger Current
MCP73832 with R3 = 10 kΩ sets about 100 mA charge current using IREG = 1000 / RPROG(kΩ). This remains conservative but lacks NTC/JEITA and power-path control.
Immediate Safety Hardening Added
  • F2 LED-branch PPTC.
  • F3 battery-side PPTC near the LiPo connector.
  • R10 external EN pull-down.
  • D2 CC1/CC2 ESD array.
  • R11/R12/C44 VBUS-present sense.
  • Removed C24-C43 per WS2812B-2020-V6 datasheet feature statement that no external peripheral components, including capacitors, are required.
  • R7/R8 battery ADC divider moved to switched PWR_EN source.
Open Stop-Ship Items
  • Select an exact protected LiPo pack with documented polarity, capacity, protection thresholds, wire gauge, and ideally NTC.
  • Consider replacing MCP73832 with a charger/power-path IC that supports NTC/JEITA, safety timer, input OVP, and load sharing.
  • Add true reverse-polarity protection if unkeyed/alternate-polarity battery packs may be used.
  • Validate LED branch current, surface temperature, optical brightness/strobing, and fault behavior in enclosure.
  • Re-check LED rail stability/noise on the actual PCB without per-LED capacitors; retain C5 bulk capacitance on the 3V3_LED branch.
  • Use RP2350 reference regulator layout and a polarity-marked 3.3 uH inductor, or validate the chosen alternative.
  • Do not charge while worn until enclosure, cable strain relief, thermal, and child-safety tests pass.

  • Status

  • Selected Power Architecture

  • Load Budget

  • Regulator Check

  • Charger Current

  • Immediate Safety Hardening Added

  • Open Stop-Ship Items