Hello All,
I am working on boost converter based on TPS61288RQQR, to be able supply electro locks in pulse mode (power on up to 1 second). Can you check, if my calculations are correct and batteries will handle that? Is PCB design correct?
Performance requirements:
- Vout – 8V
- Iout – up to 0,8A
Converter should give approximately 6,7W (including 95% efficiency) as output
Supply source:
- two batteries ER34615M (3,7V Lithium Thionyl Chloride) connected parallel
- Battery parameters (one cell):
- Voltage range 2,0V – 3,7V
- Nominal voltage: 3,6V
- continuous discharge current – 2A (4A for two batteries)
Based on above maximum power from two batteries is 14,4W.
I checked also voltage drop on battery pack loaded by power supply (current control). Results:
- At 1A measured 3,2V (3,2W)
- At 2A measured 2,95V (5,9W)
6,7W should be reached at 2,7V (need to be confirmed).
Summary: Supply source should handle boost converter.
Design parameters:
- Vin – 2,7V to 3,7V
- Vout – 8V
- Iout – up to 0,8A
Schematic:
Efficiency chart:
Efficiency at 0,8A is 93%, so boost converter required 6,88W as input – need to be confirmed, if battery pack is able to achieve that. In worst case scenario design performance will be reduced to 0,7A.
PCB design (coil will be changed):
PCB parameters:
- Laminate type: FR4
- Laminate thickness: 1,5mm
- Copper thickness: 35 um
- 2 layers
Do I miss something?
