Blinking LED Circuit Design

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I've made a plan, and started work on it.

Started implementing a plan

#Goal

- Route the SW net on the existing 30mm x 25mm 2-layer boost converter PCB, ensuring a compact and minimal trace connection between U1:SW, L1:P2, and D1:A without disturbing other components or nets.

#Implementation plan

1. Inspect the existing PCB layout:

1. Verify and identify the SW net endpoints: U1:SW, L1:P2, and D1:A.

2. Confirm that all component placements and other net routings (FB divider, VIN, VOUT, GND) remain intact.

2. Route the SW net:

1. Use the top-layer routing to create a direct and short trace connecting U1:SW, L1:P2, and D1:A.

2. Avoid adding unnecessary vias or deviations and steer clear of the feedback divider/sense area.

3. Validate the routing:

1. Ensure that the SW trace is the only trace modified.

2. Confirm that no other net or component placement has been disturbed.

#Success criteria

- The SW net should have a minimal length and direct connection between U1:SW, L1:P2, and D1:A.

- No component placement changes or disturbances to other nets (FB, VIN, VOUT, GND) occur.

Execution stopped due to insufficient credits.

0:17

flux

Work done
  • I could not continue execution because the session has no remaining execution credits.
  • No project manipulation was performed in this step, so the existing 30mm × 25mm layout and current routing state remain unchanged.
Success criteria review
  • ❌ SW endpoints were not re-inspected in this step.
  • ❌ The SW net was not routed in this step.
  • ✅ No other components or nets were disturbed by this step.
Next steps
  • When execution is available again, proceed with: inspect U1/L1/D1 pad locations, route only the SW net on the top layer with the shortest practical path between U1:SW, L1:P2, and D1:A, then validate that FB, VIN, VOUT, GND, and component placement are unchanged.
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Boost Converter Design Notes
Captured specifications and assumptions
  • Project: Tremendous Azure Robot Vacuum auxiliary boost rail.
  • Input voltage: 3.7 V nominal single-cell Li-ion/LiPo input, with expected operating range approximately 3.0 V to 4.2 V.
  • Output voltage: 5.0 V assumed, because the requested output voltage was not provided.
  • Maximum output current: 1.0 A assumed continuous load for an auxiliary rail.
  • Output ripple target: = 85% at nominal operating conditions; final measured efficiency depends on layout, inductor DCR, diode loss, and load profile.
  • Thermal constraint: verify IC, inductor, and Schottky diode temperature rise at full load.
  • EMI/layout constraint: minimize SW loop area and keep L1, D1, C1, and C2 close to U1.
  • Solderability: selected SOT-23-6, SMA, 0805/1206, and 5.08 mm terminal block style parts for hand-soldering feasibility.
Selected topology
  • Asynchronous boost converter using MT3608.
  • MT3608 datasheet-relevant facts: 2 V to 24 V input range, 1.2 MHz switching, 4 A switch current limit, adjustable output, internal compensation, up to 28 V output, PFM light-load mode, under-voltage lockout, current limiting, and thermal overload protection.
  • L1: 4.7 uH shielded power inductor, >= 4 A saturation/current rating. This is within the MT3608 datasheet recommended 4.7 uH to 22 uH range.
  • D1: SS34 3 A / 40 V Schottky rectifier. Schottky rectification is recommended for low loss and fast recovery at the 1.2 MHz switching frequency.
  • C1: 22 uF / 16 V input capacitor, low-ESR X7R ceramic.
  • C2: 47 uF / 16 V output capacitor, low-ESR ceramic or polymer. Datasheet minimum guidance is 22 uF; 47 uF was selected to improve ripple margin.
  • R1/R2 feedback divider: 130 kOhm top, 18 kOhm bottom, targeting approximately 4.93 V using VOUT = 0.6 V x (1 + R1/R2).
Schematic connectivity
  • J1 pin 1, C1, U1 IN, U1 EN, and L1 input are on VBAT_3V7.
  • L1 output, U1 SW, and D1 anode are on SW.
  • D1 cathode, C2, R1 top, and J2 pin 1 are on VOUT_5V.
  • R1 bottom, R2 top, and U1 FB are on FB.
  • J1 pin 2, U1 GND, C1, C2, R2 bottom, and J2 pin 2 are on GND.
  • U1 NC is intentionally marked no-connect.
Validation criteria
  • Verify VOUT regulation near 5 V from 3.0 V to 4.2 V input under the intended load.
  • Confirm output ripple remains <= 50 mV peak-to-peak at the final load.
  • Check inductor saturation margin and diode/IC thermal rise at maximum load.
  • Before PCB fabrication, place C1 and C2 close to U1, keep the SW copper area small, use short/wide high-current traces, and keep the FB divider close to U1 and away from SW.
  • ERC/DRC should be reviewed after layout because clean ERC/DRC is necessary but not sufficient proof of power-converter performance.

    Captured specifications and assumptions

    Selected topology

    Schematic connectivity

    Validation criteria

Documents

    Boost Converter Design Notes

Assets

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3.7V Li-Ion Boost Converter

3.7V Li-Ion Boost Converter thumbnail
High-efficiency 3.7V Li-Ion boost converter for the Tremendous Azure Robot Vacuum auxiliary power rail.

Properties

3.7V nominal Li-ion/LiPo, expected usable range approximately 3.0V to 4.2V

Keep MT3608, diode, and inductor temperature rise acceptable under 1A load; verify with prototype or thermal simulation

>=85% target at nominal load; final value requires layout and load validation

Minimize SW loop area; place L1, D1, C1, C2 close to U1; use short wide power traces

5V assumed target because output requirement was missing

<=50mV peak-to-peak assumed with low-ESR output capacitor and compact layout

SOT-23-6 IC, SMA diode, 0805/1206 passives, and 5.08mm terminal blocks selected for hand soldering feasibility

1A assumed continuous auxiliary rail

Pricing & Availability

Distributor

Qty 1

Arrow

$0.11–$0.32

Digi-Key

$0.03–$0.69

LCSC

$0.47–$1.17

Mouser

$0.60–$0.68

TME

$0.17

Verical

$0.04–$0.56

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