Hi Team, helping a customer,
Designed the circuit according to the EVM schematic. Please see the connection of the evaluation board used for our comparison. The R11=0 resistor was resoldered and connected to a 11.5kΩ to make the output voltage to be 2.5V.
EN->ON
MODE->PFM/PWM
STOP->RUN
R11->11.5KΩ resistor
According to this schematic, I designed the circuit as follows.
EN pin-> Input voltage
MODE pin -> 1M resistor and GND
STOP pin -> GND
VSET pin -> 11.5KΩ resistor
Comparing the current cost by my designed circuit and the evaluation board.
The BOM used to assemble is as follows.
U6 |
1 |
Texas Instruments |
TPS62840DLCR |
ULTRA LOW IQ BUCK CONVERTER |
8-VFDFN |
D4 |
1 |
ON Semiconductor |
MBR120ESFT1G |
DIODE SCHOTTKY 20V 1A SOD123L |
SOD-123F |
C1 |
1 |
Murata Electronics |
GRM21BR61A476ME15L |
CAP CER 47UF 10V X5R 0805 / 47u |
0805 |
C18 |
1 |
Murata Electronics |
GRM155R61A475MEAAD |
CAP CER 4.7UF 10V X5R 0402 / 4.7u |
0402 |
R6 |
2 |
Yageo |
RC0402FR-071ML |
RES SMD 1M OHM 1% 1/16W 0402 / 1M |
0402 |
R9 |
1 |
Yageo |
RC0402FR-0711K5L |
RES SMD 11.5K OHM 1% 1/16W 0402 / 11.5k |
0402 |
L2 |
1 |
Murata Electronics |
DFE201612E-2R2M=P2 |
FIXED IND 2.2UH 1.8A 116MOHM SMD |
0806 (2016 Metric) |
C19 |
1 |
Murata Electronics |
GRM155R60G106ME44D |
CAP CER 10UF 4V X5R 0402 / 10u |
0402 |
You may consider whether the diode affects the current cost. But we have another version without diode. The designed circuit was as follows. It can be powered directly from VIN pin.
The current measured at different Vout (select R9, R10, R11, R12, respectively) are
Hoping for your assistance.
Thank you.
-Mark