ATA6834 ATMEL Corporation, ATA6834 Datasheet - Page 9

• Manufacturer Part Number: ATA6834
• Description: (ATA6833 / ATA6834) BLDC Motor Driver and LIN System Basis Chip
• Manufacturer: ATMEL Corporation

3.5
9122D–AUTO–09/09
Charge Pump
Example:
Using an external resistor R
T
t
t
t
Hence, the minimum time the external microcontroller has to wait before pin WD can be trig-
gered is in worst case t
WD pin is t
t
Other values can be set up by picking a different resistor value for R
on the value of R
Figure 3-5.
A charge pump has been implemented in order to provide sufficient voltage to operate the exter-
nal high-side power-NMOS transistors and the VG regulator, which drives the low-side
Power-NMOS transistors. The charge pump output voltage at CPOUT pin is controlled to settle
typically about 15V above the voltage at pin PBAT. A built-in supervisor circuit checks if the out-
put voltage is sufficient to operate the VG regulator and external Power-NMOS transistors. The
output voltage is accepted as good when it rises above VCP
flagged at DG2 if this minimum can not be reached or if the output voltage drops below the lower
threshold of VCP
The two shuffle capacitors should have the same value. The value of the reservoir capacitor
should be at least twice the value of one shuffle capacitor. Two external shuffle capacitors and
an external reservoir capacitor have to be provided. The typical values for the two shuffle
capacitor is 100 nF, and for the reservoir capacitor is 470 nF. All capacitors should be ceramic. It
is advisable to pick a reservoir capacitor with twice or three-times the size of the two
equally-sized shuffle capacitors. The greater the capacitors, the greater the output current
capability.
1
2
1
max
OSC
= 980
= 780
+ t
– t
2
= 12.32 µs
= 21.68 ms ±10%
min
= 6.23 ms.
T
T
max
OSC
OSC
T
= 0.9
OSC
= 12.07 ms ±10%
= 9.609 ms ±10%
WD
CPGOOD
versus R
is shown in
4 0
3 0
2 0
4 5
3 5
2 5
10
min
15
0
5
(t
due to overloading.
10
1
= 1.1
+ t
WD
WD
2
2 0
) = 19.51 ms. Thus watchdog trigger input must remain within
= 33 k ±1% results in typical parameters as follows:
Figure
ATA6833/ATA6834 [Preliminary]
t
3 0
1
= 13.28 ms. The maximum time for the watchdog trigger on
3-5.
4 0
R
T
WD
OSCmax
50
(k )
(µs)
T
OSCmin
6 0
(µs)
70
8 0
CPGOOD
9 0
WD
. A charge pump failure is
www.DataSheet4U.com
. The dependency of T
10 0
T
OSC
(µs)
OSC
9