EnerChip
™
EP Energy Processor
EnerChip
™
Energy Processor for Energy Harvesting Applications
Features
•
•
•
•
•
•
•
•
•
•
•
•
•
•
Use any type of Energy Harvesting (EH)
transducer: Light, Vibration, Thermal, RF, etc.
Advanced Maximum Peak Power Tracking
Algorithms for High Efficiency Energy Conversion
EH Transducer to System Load Impedance
Matching
Communications Interface to System MCU
Energy Status Indicators for Incoming Energy
and Storage Energy Levels
Charge Control for EnerChip CBC050 Thin Film
Energy Storage Devices
Built-in Energy Storage Protection
Temperature Compensated Charge Control
Adjustable Switchover Voltage
Low Standby Power
38 pin TSSOP Package
-20°C to +70°C or - 40°C to 85°C Temperature
Operating Range options
SMT - Lead-Free Reflow Tolerant
RoHS Compliant
CBC915
Everything is Inside the EnerChip EP
Energizing Your Innovation
Many new energy harvesting based products can be
enabled by the EnerChip™ EP:
•
Various ambient energy sources can
be harvested to power new designs
using : Photo Voltaic Cells, Piezoelectric
vibration harvesters, Thermoelectric cells,
Electromagnetic harvesters, RF Induction
charging.
Designs can use ultra low power by leveraging
the Maximum Peak Power Tracking
capabilities of the EnerChip EP
The power management communications
interface to the system MCU can be used to
create “Energy Aware” systems
Input power measurement and status
reporting
Advanced energy storage management
Uses digital power controls
The EnerChip EP uses an advanced Maximum Peak
Power Tracking (MPPT) algorithm that constantly
matches the EH transducer output impedance. MPPT is
the most efficient method of converting energy from an
EH transducer and is superior to charge accumulation
techniques that do not match the impedance of
the transducer to the power conversion stage. The
EnerChip EP operates in multiple modes and can
communicate with microcontrollers. The EP manages
all aspects of energy storage devices/peripherals and
uses intelligent power management during the start-
up initialization sequence. The EP operates at 1/10
the power of other EH power management units.
Ideal for “Internet of Things” Wireless Sensors
•
•
•
•
•
The key to designing energy harvesting-based wireless
sensors with high efficiency power conversion is
to utilize the EnerChip EP along with EnerChip
rechargeable energy storage devices. The EnerChip EP
performs the high efficiency energy conversion, energy
storage and power management. It is the key enabler
of “Zero Power” systems as shown in the following
diagram:
DS-72- 15 Rev F
©2012 Cymbet Corporation • Tel: +1-763-633-1780 • www.cymbet.com
Page 1 of 16
CBC915 EnerChip Energy Processor
EnerChip EP Solves the Challenges of Energy Harvesting
There are many exciting new applications that could use Energy Harvesting for powering devices. Unfortunately,
utilizing the “free” ambient energy surrounding a system is a complex design challenge, with many questions to
answer including:
•
•
•
•
•
•
How to interface to energy harvesting transducers?
How to convert low input power with high efficiency?
How to manage energy storage?
How to control power to the rest of the system?
How to best manage the system power states?
How to make the entire system “Energy Aware”?
The EnerChip™ Energy Processor solves these challenges by implementing an intelligent integrated approach to
Energy Harvesting Power Management.
Introducing Maximum Peak Power Tracking - the Key to High Efficiency Systems
In order to achieve maximum power transfer from an Energy Harvesting transducer, it is critical to match the
transducer impedance to the system load impedance. Therefore, Pmax is when R
T
=R
L
.
The EnerChip EP as the Energy Processing Stage serves to match the impedances of the transducer to the
power converter and decouples the system load from the energy conversion circuits while also controlling the
energy storage elements in the system.
Factory Test
DVDD
NC
DVSS
EC CHG
EN CAP CHG
RST
VGSENSE
MPPT
ECFB
CAPCHG
NC
NC
STATUS SW
AVSS
AVDD
NC
NC
NC
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
38
37
36
35
34
33
32
31
30
29
28
27
26
25
24
23
22
21
20
EN VOUT
MODE SEL3
EN VCAP
CALIBRATE
LX
CUTOFF EN
MODE SEL2
ISOLATE EN
VCAP
MODE SEL1
MODE SEL0
CUTOFF RST
RXD
TXD
NC
NC
NC
NC
NC
EnerChip Energy Processor CBC915-ACB Pin Designations
©2012 Cymbet Corporation • Tel: +1-763-633-1780 • www.cymbet.com
DS-72-15 Rev F
Page 2 of 16
CBC915 EnerChip Energy Processor
EnerChip Energy Processor CBC915 Pin Descriptions
Pin Number
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
(1)
(2)
Pin Designation
Factory Test
DVDD
NC
DVSS
EC CHG
EN CAP CHG
RST
VGSENSE
MPPT
ECFB
CAP CHG
NC
NC
STATUS SW
AVSS
AVDD
NC
NC
NC
NC
NC
NC
NC
NC
TXD
RXD
CUTOFF RST
MODE SEL0
MODE SEL1
VCAP
ISOLATE EN
MODE SEL2
CUTOFF EN
LX
CALIBRATE
EN VCAP
MODE SEL3
EN VOUT
Description - (Input or Output)
Factory test pin - leave unconnected (I)
Digital supply voltage (same as AVDD) (I)
Not used - leave unconnected (NC)
Digital ground reference (same as AVSS) (I)
EnerChip charge indicator, pin pulses low in response to STATUS SW/ (O)
(1)
Enable Capacitor Charge goes low while charging the output capacitor (O)
Tie this pin to DVDD through a 100kΩ resistor (I)
Voltage generator input - range 0V to 2.5V (I)
Maximum Peak Power Tracking indicator (O)
(1)
EnerChip charge voltage feedback input (I)
Capacitor Charge indicator; this pin pulses low in response to STATUS SW/ (O)
(1)
Not used - leave unconnected
Not used - leave unconnected
Status state switch (see Status Indicators section) (I)
Analog ground reference - tie to system ground (same as DVSS) (I)
Analog supply voltage (same as DVDD) (I)
Not used - leave unconnected
Not used - leave unconnected
Not used - leave unconnected
Not used - leave unconnected
Not used - leave unconnected
Not used - leave unconnected
Not used - leave unconnected
Not used - leave unconnected
Serial I/O transmit data out of the Energy Processer Data rate is 9600 8N1 (O)
Serial I/O receive data into the Energy Processer Data rate is 9600 8N1 (I)
A high level will cause the EnerChip to disconnect from the system load (O)
Used in conjunction with MODE SEL1 to select transducer type (I)
(2)
Used in conjunction with MODE SEL0 to select transducer type (I)
(2)
Output capacitor feedback monitor (I)
A low level will isolate all loads from the Energy Processer (0)
Not used - leave unconnected (future product enhancement) (NC)
(2)
A high level will force the EnerChip to connect to the system load (O)
Boost converter switch driver (O)
Only used in target system calibration (see Calibration Function section) (I)
When high connects the VCAP A/D pin to the output capacitor (O)
Used to select output priority or battery priority mode (I)
(2)
(not on CBC915-ACA)
When low connects power to the application system (O)
This pin must be connected to a 1 kohm pull-up resistor or resistor with series LED to the positive supply. See Figure 3 and the section titled “Status Indicators” for more information.
See “Operating Modes” section for more detail.
DS-72-15 Rev F
©2012 Cymbet Corporation • Tel: +1-763-633-1780 • www.cymbet.com
Page 3 of 16
CBC915 EnerChip Energy Processor
EnerChip Energy Processor CBC915 Operating and Maximum Parameters
Parameter
Recommended Operating Conditions
Supply voltage VDD
Supply voltage VSS
Operating temperature - CBC915-ACB
Operating temperature - CBC915-AIB
Absolute Maximum Ratings
Voltage applied at VDD to VSS
Voltage applied to any pin
Diode current at any device terminal
Storage temperature range
-0.3
-0.3
-2
-55
-
-
-
-
4.1
VDD+0.3
-2
+105
V
V
mA
°C
2.5
-
-20
-40
3.5
0
+25
+25
3.6
-
+70
+85
V
V
°C
°C
Min
Typ
Max
Unit
Notes:
1. Thermal or electrical stresses beyond those listed under absolute maximum ratings may cause permanent damage
to the CBC915. These are stress ratings only, and functional operation of the device at these or any other conditions
beyond those indicated under recommended operating conditions is not implied. Exposure to absolute maximum rated
conditions for extended periods my affect device reliability.
EnerChip Energy Processor CBC915 I/O Pin Characterization
Parameter
Positive-going input threshold voltage
Negative-going input threshold
voltage
Input voltage hysteresis
Pullup/Pulldown resistor
Input Capacitance
High impedance leakage current
VOH - High level output voltage
VOL - Low level output voltage
Internal clock frequency tolerance
for pullup, VIN=VSS
for pulldown, VIN=VDD
VIN=VSS or VDD
See notes 1 and 2
100uA
100uA
25 °C
0 to 80 °C
3.5
3.5
3.5
N/A
Conditions
VDD
3.5
3.5
3.5
Min
1.59
0.88
0.36
20
-
-
Typ
-
-
-
35
5
-
Max
2.63
1.91
-
50
-
+/- 50
VDD-0.1
VSS+0.1
-
-
Unit
V
V
V
kΩ
pF
nA
V
V
MHz
VDD-0.25 -
VSS
-
-
-
+/- 1%
+/- 2.5%
Notes:
1. The leakage current is measured with VDD or VSS applied to the corresponding pin(s) unless otherwise noted.
2. The leakage of the I/O pins is measured individually. The I/O pin is selected for input and the pullup/pulldown resistor
is disabled. All inputs except STATUS SW/ and CALIBRATE/ are high impedance inputs.
DS-72-15 Rev F
©2012 Cymbet Corporation • Tel: +1-763-633-1780 • www.cymbet.com
Page 4 of 16
CBC915 EnerChip Energy Processor
CBC915 Operation
The CBC915 performs the function of efficiently converting energy from an external power transducer to a voltage
and current usable by typical applications such as remote wireless sensors. The CBC915 performs this function
by dynamically matching its input impedance to the output impedance of the transducer. At impedance match,
maximum power will be extracted from the transducer.
Differences Among Power Transducers
There are many different types of power transducers used in energy harvesting applications; they are broadly
divided into two categories. Photovoltaic (PV) cells are unique and consequently in their own category due to
the diode-like current-voltage (IV) characteristics of PV cells. The PV cell impedance changes with changes in
incident light intensity. As the light intensity increases, the PV cell impedance decreases. For example, typical
impedance for a 30cm
2
two-series amorphous silicon cell array will be 1kΩ at 1000Lux and 5kΩ at 200Lux.
Therefore, transferring maximum power from the PV cell into CBC915 Energy Processor boost converter requires
the input impedance of the boost converter to change dynamically in response to light intensity (thus PV cell
impedance) fluctuations. Plotting a load line of current vs. voltage on a graph will show a diode-like response
curve, in contrast to a purely resistive source which having a linear load line response. When presented with
a matched impedance, the output voltage of an efficient PV cell is fairly constant over varying incident light
intensity. In contrast, the voltage at the peak power point of a less efficient voltage will change with variations
in light intensity. The CBC915 adjusts its input impedance to match the output characteristics of any type or
quality of PV cell. The CBC915 was designed to work with PV cells arrays of 1-series to 8-series cells, equating to
approximately 0.5V to 4V at matched impedance. In most cases it is most power efficient to use a PV array with
two cells in series. Series-cell configurations with fewer cells have the advantage of not losing as much efficiency
due to shading and have more efficiency per unit area because there are fewer gaps in the array that do not
contribute to energy conversion.
The power curve of Figure 1 is typical of a low power PV cell used in energy harvesting applications. Electrical
impedance of the cell varies strongly as a function of ambient light. As illustrated, the power curve is highly non-
linear, meaning that connecting an electrical load to the PV cell that is not matched to its impedance results in
inefficient power transfer to that load.
6100
5490
4880
4270
Power (I x V)
3660
3050
2440
1830
1220
610
0
0
Normalized Power From a Photovoltaic Cell
100
Voltage as a percentage of open circuit voltage
90
80
70
60
50
40
30
20
10
0
Power
Volts
10
20
30
40
50
60
70
80
90
100
Current as a percentage of short circuit current
Figure 1. Maximum Peak Power Point for Variable Resistance Transducer
©2012 Cymbet Corporation • Tel: +1-763-633-1780 • www.cymbet.com
DS-72-15 Rev F
Page 5 of 16