E981.03 Datasheet, PDF (17/51 Pages) ELMOS Semiconductor AG – Autonomous MAC and individual physical address

KNX/ EIB TRANSCEIVER
PRODUCTION DATA - JAN 15, 2015
E981.03
5.7 E981.03 System Functions
5.8 Power Supply
V_BUSP
BUSP
GND
V_{VST_drop}
bus current
source
I_REF<= I_BUSP,MAX
D
I_{LOAD_SUM}
Switch C
01 2
Switch A
V20
supply
VST
(15)
I_VST
C_ST
V20
(14)
V_VST
I_V20
C_V20 ^VV20
V33I
supply
2
I_V33I
1
Switch B
V33I
VIO
(6)
(19)
C_33I ^VV33I
C_VIO
Switch A:
Switch to 0:
Switch to 1:
Switch to 2:
Only after PON until end of soft-start
(V_VIO is in valid range >~3.1 … <~3.4V) and (V_VCC is 3.3V or
(V_VCC=5V and PFCTRL (0x20e) Bit 7 is set))
Otherwise
VCC buck
converter
Switch B:
Switch to 1: (V_VIO is in valid range >~3.1 … <~3.4V) and (V_VCC is 3.3V or
(V_VCC=5V and PFCTRL (0x20e) Bit 7 is set))
Switch to 2: Otherwise
Switch C:
Open: When V_VST is below V_V20,off,abs or V_V20,off,rel
V_VST < V_{V20,off,abs,typ} = V +1 _{VST,SAVE,HL,typ} V=14V+1V=15V
V_VST > V - _BUSP,mean 6 V
VCC
(18)
I_VCC
C_VCC
V_VCC
Close: When V_VST is above either
V and V _V20,on,abs
V20,on,rel
V_VST > V_{V20,on,abs,typ} = V +1 _{VST,SAVE,LH,abs,typ} V=15V+1V=16V
V_VST > V - _VBUSP,mean 5 V
Option 1: V_VIO supplied by V_VCC
Option 2: V_VIO supplied by external
If the I_{LOAD_SUM} is higher then I_BUSP,MAX the C_VST discharges and the voltage V_VST drops down.
Figure 6. Configurable Power Management
The supply blocks generates a 20V application volt-
age V_V20, a variable storage voltage VST, a configurable
5V/3.3V output voltage V_VCC and a 3.3V voltage V_V33I used
by internal components of the E981.03. The voltages V_V20
and V_VCC can be used to supply external components.
The voltages V_V33I is externally blocked but the strictly
recommendation is not use this pin for other supplies!
The voltage V_VST is externally blocked. Usage of this volt-
age for external supplies is not recommended because it
disturb the autonomous power management of the IC!
To prevent a overload and a fast load slope on the bus
the power management of the IC generates a variable
storage voltage V_VST. This voltage has a limited input cur-
rent I_REF and a limited slope of I_REF. The maximum current
I_REF and the maximum slope are configurable through SPI
or UART – Service. The value of V_VST in normal operation
without an overload condition is V_BUSP – V . _{VST_DROP} The
power which is continuously useable is (V_BUSP – V ) _{VST_DROP}
* I_REF. If more power is used the C_ST is discharging, V_VST
drops below V_BUSP – V . _{VST_DROP}
To prevent a unpredictable crash the supplies have the
following prioritization:
3^rd : V20
Is generated by a linear voltage regulator out of the V_ST.
It is the supply for additional circuits and has the low-
est priority. V20 is the first one drops down, to prevent
a dropping down of VCC with the consequence of a mi-
crocontroller reset. If a continuous overload is applied a
pulsing V20 is possible.
2^nd : VCC
Is generated by a step down DC/DC converter and could
supply a microcontroller with its peripheral. The output
voltage is selectable 5V or 3.3V. The supply could deliv-
er up to 30mA at 5V and 50mA at 3.3V. Before it drops
down V20 is switched of. If a continues overload condi-
tion is active V_VST drops below V_VST,SAVE,HL and the SAFE sig-
nal flags a overload condition before VCC drops down.
1^st : V33I
Supplies the IC and is the last one which drops down.
Please refer the Application Note for more details.
Elmos Semiconductor AG reserves the right to change the detail specifications as may be required to permit improvements in the design of its products.
Elmos Semiconductor AG
Data Sheet
QM-No.: 25DS0046E.03
17/51