WM9711_06 WOLFSON [Wolfson Microelectronics plc], WM9711_06 Datasheet - Page 39
![no-image](/images/no-image-200.jpg)
WM9711_06
Manufacturer Part Number
WM9711_06
Description
Low Power Audio CODEC for Portable Applications
Manufacturer
WOLFSON [Wolfson Microelectronics plc]
Datasheet
1.WM9711_06.pdf
(65 pages)
- Current page: 39 of 65
- Download datasheet (608Kb)
Production Data
w
Figure 6 Battery Alarm Example Schematic
The typical schematic for a dual threshold battery alarm is shown above. This alarm has two
thresholds, “dead battery” (COMP1) and “low battery” (COMP2). R1, R2 and R3 set the threshold
voltages. Their values can be up to about 1MΩ in order to keep the battery current [I
(R1+R2+R3)] to a minimum (higher resistor values may affect the accuracy of the system as leakage
currents into the input pins become significant).
•
A dead battery alarm is the highest priority of interrupt in the system. It should immediately save all
unsaved data and shut down the system. The GP15, GS15 and GW15 bits must be set to generate
this interrupt.
•
A low battery alarm has a lower priority than a dead battery alarm. Since the threshold voltage is
higher than for a dead battery alarm, there is enough power left in the battery to give the user a
warning and/or shut down “gracefully”. When V
alarms are filtered out by the COMP2 delay function.
The purpose of the capacitor C is to remove from the comparator inputs any high frequency noise or
glitches that may be present on the battery (for example, noise generated by a charge pump). It
forms a low pass filter with R1, R2 and R3.
•
Provided that the cutoff frequency is several orders of magnitude lower than the noise frequency f
this simple circuit can achieve excellent noise rejection.
•
Dead battery alarm: COMP1 triggers when V
Low battery alarm: COMP2 triggers when V
Low pass cutoff f
Noise rejection [dB] = 20 log (f
V
BATT
REGULATOR
VOLTAGE
I
ALARM
c
[Hz] = 1/ (2π C × (R1 || (R2+R3)))
R1
AVDD, DCVDD, ...
R2
R3
n
/ f
C
COMP1
COMP2
c
)
BATT
BATT
BATT
gets close to the low battery threshold, spurious
< VREF × (R1+R2+R3) / R3
< VREF × (R1+R2+R3) / (R2+R3)
+
-
-
+
V
REF
DEAD
LOW
BAT
BAT
GPIO2/
IRQ
INTERRUPT
WM9711L
GPIO /
LOGIC
PD Rev 4.3 August 2006
GPIO
PINS
WM9711L
ALARM
= V
BATT
39
n
/
,
Related parts for WM9711_06
Image
Part Number
Description
Manufacturer
Datasheet
Request
R
![WM9711](/images/no-image3.png)
Part Number:
Description:
Manufacturer:
Wolfson Microelectronics plc
Datasheet:
![WM8351CGEB/RV](/images/no-image3.png)
Part Number:
Description:
Wolfson AudioPlus™ Stereo CODEC with Power Management
Manufacturer:
WOLFSON [Wolfson Microelectronics plc]
Datasheet:
![WM9701A](/images/no-image3.png)
Part Number:
Description:
WM9701ALow Power AC97 Multimedia Audio Codec
Manufacturer:
WOLFSON Wolfson Microelectronics plc
Datasheet:
![WM8973LGEFL](/images/no-image3.png)
Part Number:
Description:
WM8973LGEFLSTEREO CODEC FOR PORTABLE AUDIO APPLICATIONS
Manufacturer:
WOLFSON Wolfson Microelectronics plc
Datasheet:
![wm8350](/images/no-image3.png)
Part Number:
Description:
Wolfson Audioplus? Stereo Codec With Power Management
Manufacturer:
Wolfson Microelectronics plc
Datasheet:
![wm8351](/images/no-image3.png)
Part Number:
Description:
Wolfson Audioplus? Stereo Codec With Power Management
Manufacturer:
Wolfson Microelectronics plc
Datasheet:
![wm8352](/images/no-image3.png)
Part Number:
Description:
Wolfson Audioplus? Stereo Codec With Power Management
Manufacturer:
Wolfson Microelectronics plc
Datasheet:
![wm2000](/images/no-image3.png)
Part Number:
Description:
Handset Receiver Speaker Driver With Wolfson Myzone Ambient Noise Cancellation
Manufacturer:
Wolfson Microelectronics plc
Datasheet:
![wm2002](/images/no-image3.png)
Part Number:
Description:
Stereo Headphone Driver With Wolfson Myzonetm Ambient Noise Cancellation
Manufacturer:
Wolfson Microelectronics plc
Datasheet:
![wm8400](/images/no-image3.png)
Part Number:
Description:
Wolfson Audioplustm Hi-fi Audio Codec And Power Management Unit For Mobile Multimedia
Manufacturer:
Wolfson Microelectronics plc
Datasheet:
![WM9701A](/images/no-image3.png)
Part Number:
Description:
WM9701ALow Power AC97 Multimedia Audio Codec
Manufacturer:
WOLFSON Wolfson Microelectronics plc
Datasheet:
![WM8973LGEFL](/images/no-image3.png)
Part Number:
Description:
WM8973LGEFLSTEREO CODEC FOR PORTABLE AUDIO APPLICATIONS
Manufacturer:
WOLFSON Wolfson Microelectronics plc
Datasheet:
![WM9711](/images/no-image3.png)
Part Number:
Description:
Manufacturer:
Wolfson Microelectronics plc
Datasheet:
![WM9705](/images/no-image3.png)
Part Number:
Description:
Manufacturer:
Wolfson Microelectronics plc
Datasheet:
![WM9707](/images/no-image3.png)
Part Number:
Description:
Manufacturer:
Wolfson Microelectronics plc
Datasheet: