e-peas AEM00901 Stamp Module User Guide

: June 9, 2024
: e-peas

Table of Contents

e-peas AEM00901 Stamp Module
Description
Appearance
Features
Applications
Connections Diagram
General Considerations
Functional Tests
Schematics
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e-peas AEM00901 Stamp Module

Description

The AEM00901 evaluation kit (EVK) is a printed circuit board (PCB) featuring all the required components to operate the AEM00901 integrated circuit (IC).
The AEM00901 evaluation board allows user to test the e-peas IC and analyse its performances in a laboratory-like setting or in product mock-ups.
It allows easy connections to an energy harvester (e.g. a single element PV cell) and a storage element. It also provides all the configuration access to set the device in any of the modes described in the datasheet at the exception of SRC_LVL_CFG[5], which has been tied to ground. The control and status signals are available on pads or through an I²C bus communication, allowing user to over-ride preconfigured board settings through host MCU and evaluate the IC performances.
The AEM00901 EVK is a plug and play, intuitive and efficient tool to optimize the AEM00901 configuration, allowing user to design a highly efficient subsystem for the desired target application. Component replacement and operating mode switching is convenient and easy.
More detailed information about AEM00901 features can be found in the datasheet.

Appearance

Features

Key features

Very high efficiency conversion from single element PV
Very low BOM
Very small footprint
Ready to use without MCU interaction
Optional configuration through I²C
Thermal monitoring

Breakout solder pads

Connection to DC source of energy (PV)
Connection to storage element
AEM Internal voltage
Temperature monitoring
Reset
I²C slave (address 0x41)
Configuration

Additional two solder pads

Connection to DC source of energy (PV)
Connection to storage element

20 solder bridges and one resistor

ZMPP configuration
Constant source voltage (SRC_LVL_CFG) configuration
Energy storage element threshold configuration
Mode configuration

Applications

Wearable Electronics Keyboards
Remote Control Units Electronic Shelf Labels
Smart Buildings Indoor Sensors

Device Information

Part Number	Dimensions
3JAEMEXSPEX221 REV:1	20 mm x 20 mm

Connections Diagram

e-peas-AEM00901-Stamp-Module-fig
1

Figure 1: Connection diagram

Signals Description

NAME	FUNCTION	CONNECTION
If used	If not used

BUFSRC

| AEM connection to a capacitor buffering the boost converter input (no connector on EVK).| |
Configuration signals
SRC_LVL_CFG[5:0]| Used for the configuration of the source voltage level.| Connect solder bridge.| Read as high if left floating.

STO_CFG[2:0]

| Configuration of the threshold voltages for the energy storage element.|

Connect solder bridge.

| ****

Read as high if left floating.

KEEP_ALIVE

| Enabling pin to supply internal circuitry from the storage element if no power on SRC| ****

Connect solder bridge.

| ****

Read as high if left floating.

I²C signals
SDA| Bidirectional data line| ****

Connect to host I²C bus.

General Considerations

Safety Information

Always connect the elements in the following order:

Reset the board: do the following in this particular order:
- Disconnect the harvester from SRC.
- Short BUFSRC to GND.
- Short VINT to GND.
Completely configure the PCB (jumpers/resistors):
- Battery configuration.
- Mode configuration.
- Thermal monitoring configuration.
Connect I2C_VDD:
- To GND if I²C is not used (SDA and SCL will also be connected to GND through their pull up resistors).
- To a power supply if I²C is used (1.5 V to 2.2 V).
Connect the storage elements on STO with a voltage higher than 2.8V.
Connect the source to the SRC connector (open circuit voltage lower than 2.0 V).

Basic Configurations
On the Stamp Module, the MSB of the SRC_LVL_CFG[5:0] pins has been tied to ground.

Configuration pins	Voltage Level
SRC_LVL_CFG[5:0]	VSRC,REG
0	0
0	0
0	0
0	0
0	0
0	0
0	0
0	0
0	0
0	0
0	1
0	1
0	1
0	1
0	1
0	1
0	1
0	1
0	1
0	1
0	1
0	1
0	1
0	1
0	1
0	1

Table 2: Configuration of SRC_LVL_CFG[5:0]

Configuration| Availability Through Pins| Storage element threshold voltage
---|---|---
CFG[2:0]| I²C Interface| Configuration pins| Vovch| Vovdis
000| yes| yes| 4.50 V| 3.30 V
001| yes| yes| 4.00 V| 2.80 V
010| yes| yes| 3.63 V| 2.80 V
011| yes| yes| 3.90 V| 2.80 V
100| yes| yes| 3.90 V| 3.50 V
101| yes| yes| 3.90 V| 3.01 V
110| yes| yes| 4.35 V| 3.01 V
111| yes| yes| 4.12 V| 3.01 V

Table 3: Usage of CFG[2:0]

I²C Register Map

Address| Name| Bit| Field Name| Access| RESET| Description
---|---|---|---|---|---|---
0x00| VERSION| [3:0]| MINOR| R| –| Chip ID
[7:4]| MAJOR| R| –|
0x01| SRCREGU| [6:0]| VALUE| R/W| 0x77 (1.47V)| Source voltage regulation
0x02| VOVDIS| [5:0]| THRESH| R/W| 0x2D (3.05V)| Overdischarge level of the storage

element

0x03| VOVCH| [5:0]| THRESH| R/W| 0x33 (4.1V)| Overcharge level of the storage element
0x04| TEMPCOLD| [7:0]| THRESH| R/W| 0x8F (0°C)| Cold temperature level
0x05| TEMPHOT| [7:0]| THRESH| R/W| 0x2F (45°C)| Hot temperature level

0x06

| ****

PWR

| [0:0]| KEEPALEN| R/W| 0x01| Keepalive enable
[1:1]| HPEN| R/W| 0x01| AEM00900: High power mode enable

AEM00901: Reserved

[2:2]| TMONEN| R/W| 0x01| Temperature monitoring enable
[3:3]| STOCHDIS| R/W| 0x00| Battery charging disable
0x07| SLEEP| [0:0]| EN| R/W| 0x01| Sleep mode enable
0x08| STOMON| [2:0]| RATE| R/W| 0x00| ADC rate

0x09

| ****

APM

| [0:0]| EN| R/W| 0x00| APM enable
[1:1]| MODE| R/W| 0x00| APM mode
[3:2]| WINDOW| R/W| 0x00| APM computation window

0x0A

| ****

IRQEN

| [0:0]| I2CRDY| R/W| 0x01| IRQ serial interface ready enable
[1:1]| VOVDIS| R/W| 0x00| IRQ STO OVDIS enable
[2:2]| VOVCH| R/W| 0x00| IRQ STO OVCH enable
[3:3]| SLPTHRESH| R/W| 0x00| IRQ SRC LOW enable
[4:4]| TEMP| R/W| 0x00| IRQ temperature enable
[5:5]| APMDONE| R/W| 0x00| IRQ APM done enable
0x0B| CTRL| [0:0]| UPDATE| R/W| 0x00| Load I²C registers configuration
[2:2]| SYNCBUSY| R| 0x00| Synchronization busy flag

0x0C

| ****

IRQFLG

| [0:0]| I2CRDY| R| 0x00| IRQ serial interface ready flag
[1:1]| VOVDIS| R| 0x00| IRQ STOR OVDIS flag
[2:2]| VOVCH| R| 0x00| IRQ STOR OVCH flag
[3:3]| SLPTHRESH| R| 0x00| IRQ SRC LOW flag
[4:4]| TEMP| R| 0x00| IRQ temperature flag
[5:5]| APMDONE| R| 0x00| IRQ APM done flag

0x0D

| ****

STATUS

| [1:1]| VOVDIS| R| 0x00| Status STO OVDIS
[2:2]| VOVCH| R| 0x00| Status STO OVCH
[3:3]| SLPTHRESH| R| 0x00| Status SRC LOW
[4:4]| TEMP| R| 0x00| Status temperature
[6:6]| CHARGE| R| 0x00| Status STO CH
0x0E| APM0| [7:0]| DATA| R| 0x00| APM data 0
0x0F| APM1| [7:0]| DATA| R| 0x00| APM data 1
0x10| APM2| [7:0]| DATA| R| 0x00| APM data 2
0x11| TEMP| [7:0]| DATA| R| 0x00| Temperature data
0x12| STO| [7:0]| DATA| R| 0x00| Battery voltage
0x13| SRC| [7:0]| DATA| R| 0x00| SRC ADC value

Table 4: Register summary

I²C Communication
The device address on the I²C bus is 0x41. All information about the I²C communication is available in the AEM00901 datasheet in the “System configuration” Section.
I2C_VDD must be connected to an external power supply which voltage is within the 1.5 V to 2.2 V range. On the Stamp Module, 1 kΩ pull-up on SDA and SCL (R1 and R2) to I2C_VDD are provided.
In case the configurations are set by I²C communication, the configuration pins will not be taken into account anymore.

Advanced Configurations
A complete description of the system constraints and configurations is available in Section “System configuration” of the AEM00901 datasheet.

Mode Configuration
DIS_STO_CH
Enabling/disabling battery charging can be done by setting a solder bridge on the corresponding pad.

Use a solder bridge to connect the DIS_STO_CH to STO to disable the charge of the storage element
Use a solder bridge to connect the DIS_STO_CH to GND to enable the charge of the storage element

KEEP_ALIVE
The KEEP_ALIVE feature allows to supply the internal circuitry from the storage element when no power is available on the source terminal.

Use a solder bridge to connect the KEEP_ALIVE to H to enable the feature
Use a solder bridge to connect the KEEP_ALIVE to L to disable the feature

Thermal monitoring
The thermal monitoring feature protects the battery by disabling the battery charging when ambient temperature is outside a specified range. The higher and lower thresholds are configurable using the I²C communication (see datasheet).

Thermal monitoring is enabled by default on the Stamp Module. To disable it, user must connect “TH_MON” (pin 10, see Figure 1) to VINT (pin 9) externally.

Functional Tests

NOTE: Out of the box testing below can be done without any modification of the Stamp Module.
This section presents a few simple tests that allow user to understand the functional behaviour of the AEM00901. To avoid damaging the board, follow the procedure found in Section 2.1 “Safety Information”. If a test has to be restarted, make sure to properly reset the system to obtain reproducible results.
The measurements use the following equipment:

Two Source Measurement Units (SMU, fourquadrant power supply)
One 2-channel oscilloscope

The following functional tests were made using the following setup:

Default configuration of the Stamp Module:
SRC_LVL_CFG[5:0] = (L)HHLHL (0.54 V).
STO_CFG[2:0] = HHH (3.01 V – 4.12 V).
DIS_STO_CH = L.
KEEP_ALIVE = H.
Thermal Monitoring is enabled by default.
Place a solder bridge to connect I²C _VDD and GND if the I²C communication is not used.

User can adapt the setup to match the use case system as long as the input limitations are respected, as well as the minimum storage voltage and cold- start constraints (see “Introduction” Section of AEM00901 datasheet).

Start-up
The following example allows the user to observe the start-up behaviour of the AEM00901.

Setup

Place oscilloscope probes on VINT and STO.
Referring to Figure 1, follow steps 1 to 5 explained in Section 2.1 “Safety Information”.
STO: SMU set as a 3.0 V voltage source with 1 mA current compliance.
SRC: SMU set as a 1 mA or 100 μA current source with 0.8 V voltage compliance.

Observations and measurements

VINT: voltage rises to 2.2 V
STO: observe the current absorbed by the SMU as power is transferred from SRC to STO.

Shutdown
This test allows user to observe the behaviour of the AEM00901 when the system is running out of energy. This test is to be done when the AEM00901 already started, as at the end of the test described in Section 3.1.

Setup

Disable the KEEP_ALIVE feature (KEEP_ALIVE = L).
Place the oscilloscope probe on VINT.
Referring to Figure 1, follow steps 1 to 5 explained in Section 2.1 “Safety Information”. Configure the board in the desired state and start the system (see Section 3.1).
Disconnect the SMU from SRC.

Observations and measurements

VINT: voltage falls to GND
STO: no leakage from STO (probe impedance considered)

Cold start
The following test allows user to observe the minimum voltage required to coldstart the AEM00901. To prevent current leakage caused by the probe impedance, user should avoid probing any unnecessary node. Make sure to properly reset the board to observe the cold-start behaviour.

Setup

Place oscilloscope probe on SRC.
Referring Figure 1, follow steps 1 to 3 explained in Section 2.1.
SRC: SMU set as 20 μA current source with 0.3 V voltage compliance.
STO: SMU as 3.0 V voltage source with 100 μA current compliance.

Observations and measurements

SRC voltage clamped at the cold-start voltage during the cold-start phase and then regulated at the selected source voltage when cold start is over. The duration of the cold-start phase decreases as the input power increases. Select the input power accordingly to be able to observe the cold-start phase.
STO: SMU starts absorbing current sourced by the STO pin once the cold-start phase is completed.

Thermal monitoring
The following test allows user to observe the thermal monitoring functionality.

Setup

Place a 10 kΩ NTC thermistor with β = 3380 on Rth.
Place a 22 kΩ pullup resistor on RDIV.
Place the jumper to connect TH_MON with THERM.
Place the probes on the nodes to be observed.
Referring to Figure 1, follow steps 1 to 5 as explained in Section 2.1 “Safety Information”. Configure the board in the desired state and start the system (see Section 3.1).

Observations and measurements

If the temperature is lower than 0°C, the charge of the storage element is disabled.
If the temperature is higher than 45°C, the charge of the storage element is disabled.
If the temperature is between 0°C and 45°C, the charge of the storage element is enabled.

Keep-alive
The KEEP_ALIVE feature sets the behaviour of the AEM00901 when no power is available on SRC.

Setup

Place the oscilloscope probe on VINT.
Referring to Figure 1, follow steps 1 to 5 explained in Section 2.1 “Safety Information”. Configure the board in the desired state and start the system (see Section 3.1).
Enable the KEEP_ALIVE feature (connect KEEP_ALIVE to H).
Disconnect the SMU from the SRC pin.

Observations and measurements

VINT: the internal circuitry is supplied by the storage element (VVINT does not drop).

Disable Storage Element Charge
To disable battery charging, the 3-pin header is available.

Use a solder bridge to connect DIS_STO_CH to L to enable the charge of the storage element
Use a solder bridge to connect DIS_STO_CH to H to disable the charge of the storage element

I²C Communication
This test allows user to change a configuration through the I²C communication.

Setup

Place the oscilloscope probe on SRC.
Referring to Figure 1, follow steps 1 to 5 explained in Section 2.1 “Safety Information”. Configure the board in the desired state and start the system (see Section 3.1).
Connect I²C _VDD to the I²C supply (between 1.8 V and 2.2 V).
Write ‘0010 0011’ (0x23) on the SRCREGU register (0x01), so that constant source voltage is set to 0.285 V)
Write ‘1’ to the CTRL register (0x0B) to load the I²C register configuration (at startup the AEM00901 load its configuration from the pins settings).

Observations and measurements

SRC: observe that the voltage regulation switches from 0.54 V to 0.285 V, when the register value is loaded.

Efficiency
This test allows user to reproduce the efficiency graphs of the boost converter (see “DCDC Conversion Efficiency” Section if the AEM00901 datasheet).

Setup

Referring to Figure 1, follow steps 1 to 5 explained in Section 2.1 “Safety Information”. Configure the board in the desired state and start the system (see Section 3.1).
STO: connect SMU configured as a 4.7 V voltage source with a 100 mA current compliance.
SRC: connect SMU configured as a source current with a voltage compliance of 1.0 V to ensure the AEM00901 coldstarts.

Manipulations

STO: set the SMU to the desired voltage, between VOVDIS and VOVCH. Make sure the SMU integration time is as long as possible.
SRC: sweep the source level voltage by either changing the SRC_LVL_CFG[5:0] pins connections (solder bridge) or by writing the SRCREGU register by I²C communication.

Observations and measurements

For each data point of the SRC voltage sweep, note the SRC SMU voltage and current, as well as the STO SMU voltage and current. Repeat the measurement for each data point a copious number of times to ensure capturing current peaks.
The efficiency η in percent is computed by applying the following formula: